Seahorse Club
Aquarium & Livestock

Feed Ezy Frozen Mysis

Seahorse Club
Aquarium & Livestock

Feed Ezy Frozen Mysis

Seahorse Club
Aquarium & Livestock

Feed Ezy Frozen Mysis

Seahorse Club
Aquarium & Livestock

Feed Ezy Frozen Mysis

Seahorse Club
Aquarium & Livestock

Feed Ezy Frozen Mysis

Seahorse Club
Aquarium & Livestock

Feed Ezy Frozen Mysis

Suspected Fin Rot

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    Hello Pete,

    It has been a while since we spoke and things have been running fairly smoothly in my seahorse tank. However my luck may have run out today… I came home to discover that my large male has developed a white line all along his dorsal fin. It is a thick line, I am surprised how quickly it has developed because I notice no signs of it while feeding them last night or this morning. I will try to post a photo once my camera is charged up. He is eating and still fairly active.

    I don\’t see any signs of similar fin abnormalities in my other horses, however I do have one that developed a weak snick a few days ago. I assumed it was from injury or muscle strain, but could it be related to the fin issue in any way? I think she is starting to improve and eating enough to get her by while she heals.

    The only thing I can think of is fin rot. I do not have a hospital tank set up but can make one with my 20 gallon using water, live rock and a used sponge, all from my established display tank, would that be a good idea?? What should I treat him with?

    Thanks Pete.

    Pete Giwojna

    Dear Claire:

    No worries — the photos came through great and I can see exactly what you’re talking about. It does appear as though your stallion has developed an infection that is attacking his dorsal fin; it may be bacterial fin rot or it may be due to a fungal infection, or a mixed bacteria/fungal problem. The white line along the dorsal fin is indeed considerably heavier then I have seen in most cases of classic fin rot, which makes me think that there could be some fungal involvement. But that really doesn’t matter, since the treatment I am going to recommend in your case should be effective whether the infection is due to bacteria, fungus, or both.

    Incidentally, I don’t believe your male’s dorsal fin problem is in any way related to the weak snick you mentioned. The dorsal infection is either bacterial or fungal in nature, whereas cases of weeks neck that are not the result of a mechanical injury can normally be attributed to a problem with protozoan parasites. That is not at all what I’m seeing here in the photographs of the affected stallion…

    Fin rot is normally not highly contagious at all, Claire — it typically sets in as a secondary infection at the site of an injury — but I am going to recommend that you treat your seahorse in a hospital tank anyway because some of the medications that are useful for this type of problem would be harmful to the biological filtration in your main tank, and would cause more problems then they help as a result if they were used in your display tank.

    Establishing a hospital tank using water and a bioactive sponge from your main tank is a good idea, Claire, but I would not use any live rock or live sand, which may absorb or react with the medications you will be using, and therefore interfere with their effectiveness. The hospital tank does not need to be very elaborate at all, as discussed below:

    The Hospital Tank

    Live sand and live rock are not necessary in a hospital tank. A bare-bottomed aquarium with plenty of hitching posts will suffice for a hospital ward or Quarantine Tank (QT). Ideally, the hospital tank should have one or more foam filters for biofiltration along with a small external filter, which can easily be removed from the tank during treatment but which can hold activated carbon or polyfilter pads when it’s time to pull the meds out. It’s important for the hospital ward to include enough hitching posts so that the seahorse won’t feel vulnerable or exposed during treatment. Aquarium safe, inert plastic plants or homemade hitching posts fashioned from polypropylene rope or twine that has been unraveled and anchored at one end are excellent for a hospital tank. No aquarium reflector is necessary. Ambient room light will suffice. (Bright lights can breakdown and inactivate certain medications and seahorses are more comfortable and feel more secure under relatively dim lighting.)

    So just a bare tank with hitching posts is all you need for your hospital ward. No heater. No reflector. No lights. No substrate. You can even do without the sponge filters or external filter in your case, just adding a couple of airstones to provide surface agitation and oxygenation. That’s it.

    In a pinch, a clean 5-gallon plastic bucket (new and unused, NOT an old scrub bucket!) can serve as a makeshift hospital tank. It should be aerated and equipped with hitching posts and perhaps a heater, but nothing else. This makes a useful substitute when the Quarantine Tank is occupied or in use and a seahorse needs treatment.

    Stay on top of water quality in the hospital tank/bucket with water changes as often as needed during treatment, and and when you are treating the occupants for a health problem, re-dose with the medication(s) according to directions after each water change.

    For what it’s worth, Claire, here is some additional information on fin rot excerpted from my new book (Complete Guide to the Greater Seahorses in the Aquarium, unpublished):

    Fin Rot

    This condition usually begins as a white line along the margin of the fin and, as the infection progresses and the membrane of the fin gets eaten away, the rigid fin rays become exposed and the fin frays as a result. As long as you detect the condition early and begin treatment before the fin is eroded away all the way to the body, allowing the infection to invade the underlying musculature, the chances for a complete recovery are very good and the damage to the fin will quickly regenerate itself once the infection is eliminated. For example, this is how I described fin rot in my old "Step-By-Step Book about Seahorses:"

    <open quote>
    Fin Rot in Seahorses

    "Fin rot is another problem that sometimes afflicts seahorses in captivity. When this happens, the alert aquarist will notice that the fins of the seahorse are beginning to look frayed and ragged for no apparent reason. This damage is most obvious in the dorsal fin, which is almost always the first to be attacked. In its early stages, this disease is evident as a fine white line along the edge of the fin, which gradually advances towards the base of the fin until the fin rays become exposed, protruding like the ribs of a tattered umbrella. If the bacterial rot is left untreated, the entire fin will be destroyed and the body tissues of the seahorse will become infected, at which point it can no longer be saved. Early detection and treatment is crucial for curing fin rot. At the first sign of fin rot, Mildred Bellamy recommends submerging the infected seahorse in a numeral 1:4000 solution of copper sulfate for one to two minutes. As she cautions, fishes undergoing this chemical baths should be watched closely and removed at the slightest sign of distress regardless of how much time has elapsed. A second bath should be administered in exactly the same manner 24 hours later. Along with these chemical dips, she also recommends that the infected fins be swabbed with a good bacteriocidal agent, such as hydrogen peroxide or merbromin (brand name Betadine), three or four times daily for a period of five to seven days. It may also be helpful to gradually lower the specific gravity of the aquarium water to about 1.020 during treatment, since fin rot is sometimes associated with high salinity.

    "Providing the fin rot is detected early, or is only a mild infection, seahorses usually recover completely following this regimen of treatment, and the damaged fin will be fully regenerated. Once again, I must stress the fact that the key to recovery is stopping fin rot in its tracks before the bacteria penetrates the tissue and the body of the seahorse becomes infected." (Giwojna, Step-By-Step Book about Seahorses, pp. 57-58) <end quote>

    Nowadays, of course, we have much better treatments at were available in Mildred Bellomy days, and I would not bother with copper sulfate at all. Rather, I would recommend treating the affected seahorses with antibiotic therapy in your hospital tank or bucket.

    In your case, Claire, I am going to recommend a two-step treatment process that should be effective against either bacteria or fungus or both. The first step would be to administer a quick formalin bath to your seahorse, and then to transfer him directly to your hospital tank for further treatment following the formalin dip. Here are the instructions for performing the formalin bath:

    Formalin Bath

    Formalin (HCHO) is basically a 37% solution of formaldehyde and water. It is a potent external fungicide, external protozoacide, and antiparasitic, and is thus an effective medication for eradicating external parasites, treating fungal lesions, and reducing the swelling from such infections. It is a wonder drug for treating cases of Popeye caused by trematodes, and also eradicates external nematodes.

    Formalin can also be useful in treating fish with the following clinical symptoms:

    Increased respiration; loss of normal body color; presence of discrete white spots (freshwater or saltwater "ich"); white areas on the body with circumscribed, reddish perimeter (Epistylis and/or bacterial infection); scratching on tank bottom or objects, lethargy, white cottony tufts or strands on body (fungus); dust-like, "peppered", yellowish spots on body surface (Oodinium); whitish skin slime or filmy body covering or patches (columnaris disease); disintegrating fins or fin edges (fin rot); mouth "fungus" (bacterial infection); pustules, furuncules or ulcers.

    If any of the above symptoms are similar to the problems you’ve noticed with your seahorses upon close inspection, then administering formalin baths to the seahorses may be helpful.

    In my experience, provided it is administered properly, seahorses tolerate treatment with formalin very well at therapeutic dosages. For a long term bath the correct dose is 15 to 25 mg/L. [Note: 25 mg/L equals 1 ml (cc) of 37% formalin per 10 gallons of water.] This is done every other day for 3 treatments.

    For a short term bath (dip) the correct dose is 250 mg/L. This would equal 1 ml (cc) of 37% formalin per 1 gallon of water. This should be for about 45 minutes to 1 hour. In my opinion, formalin is a safe, effective treatment for parasitic infections in seahorses providing you don’t exceed these dosages and observe the following precautions for administering the medication properly:

    Many commercial formalin products are readily available to hobbyists, such as Kordon’s Formalin 3, Formalin-F sold by Natchez Animal Supply, and Paracide-F, sold by Argent go to top Chemical Laboratories. Or whatever brand of formalin is available at your fish store should work fine, Claire. In your case, I am recommending a short-term bath in formalin as described below, after which you can release the seahorse in your hospital tank for further treatment:

    A formalin bath simply involves immersing the seahorse in a container of saltwater which contains the proper dosage of formalin for a period of 30-60 minutes before transferring it to your hospital tank. Include a hitching post of some sort in the container and follow these instructions: place the fish in a three-gallon bucket or a similar clean, inert container containing precisely one gallon of siphoned, aerated tank water. Medicate the bucket of water with with the appropriate amount of formalin for a concentrated bath according to the directions on the label. Place an airstone in the bucket and leave the fish in the bath for 30 minutes. If at any time the fish becomes listless, exhausted or loses its balance, immediately place the fish in clean, untreated water in your hospital tank.

    I want you to be aware of these precautions when administering the formalin bath:
    Formalin has limited shelf life and degrades to the highly toxic substance paraformaldehyde (identified as a white precipitate on the bottom of the solution); avoid using any formalin product which has such a precipitate at the bottom of the bottle.
    Formalin basically consumes oxygen so vigorous aeration must be provided during treatment.
    Time the bath closely and never exceed one hour of chemical exposure at this concentration.
    Observe the seahorse closely during the bath at all times, and it show signs of distress before the allotted time has elapsed, remove it from the treatment immediately.

    If you can obtain Formalin 3 from Kordon at your LFS, Claire, these are the instructions you should follow for your formalin dip:

    (a) To a clean, non-metallic container (i.e., a plastic bucket), add one or more gallons of fresh tap water treated with Kordon’s AmQuel . For marine fish use freshly prepared saltwater adjusted to the same specific gravity (or salinity) as in the original tank. Make sure the temperature in the container is identical to that in the aquarium
    (b) Add 1 teaspoons of Formalin·3. This produces a concentration of 100 ppm. formaldehyde.
    (c) Agitate the solution with an airstone and adjust for a moderately strong flow of air.
    (d) Remove the fishes to be treated and deposit them in the container for a treatment period of not more than 50 minutes. Immediately after the treatment period, or if signs of distress are noted, remove the fishes to a previously prepared recovery tank. The fishes may be returned to their original tank, but the presence of the original disease-causing agents in the tank water may result in a reoccurrence of the disease condition.
    (e) Observe recovering fishes. Make sure that tankmates do not molest them during recovery.
    (f) Repeat treatment as needed, every week. Each treatment is very stressful to the treated fishes. Do not reuse the dip solution.

    For additional information on treating fishes with Formalin 3 by Kordon, see the following web page:

    Click here: KPD-54 Formalin-3

    If you get another brand of formalin, just follow the instructions that it comes with for a concentrated bath or dip (not prolonged immersion or a long-term bath).

    You should have your hospital tank or treatment tank set up using water and an established sponge from your display tank before you perform the formalin bath so that the seahorse tank can then be transferred directly to the hospital tank following the formalin bath for further treatment. Once your seahorse has been released in the hospital tank, I recommend treating him with acriflavine and Furan2 used together.


    This is a powerful stain, sometimes known as a tanning agent due to cross-linking of proteins it causes (Burns, 2000). It belongs to a class of drugs known as acridines, which bond to the nucleic acids of disease causing organisms. The resulting cross-linking damage kills microbes (some bacteria, fungus, and especially ectoparasites).

    Acriflavine is useful for the treatment of open wounds, external protozoan infections and skin parasites, and the control of Columnaris bacterial infections (Flexibacter sp.). Consider using it when seahorses show the following symptoms: increased respiration, loss of normal body color, scratching themselves with their tails or scratching or on objects; lethargic behavior, randomly distributed powdery or dust-like spots on their body, having a yellowish cast (Oodinium); frayed fins, body lesions with reddish color and diffuse white areas (Flexibacter).

    The best thing about Acriflavine is that it is very safe. Fish tolerate it very well and it does not effect biofiltration so it can be used to treat the main tank. Acriflavine can be use with methylene blue to aid respiratory distress and increase its effectiveness against protozoan parasites.

    Acriflavine is sensitive to strong light and UV and will decompose in their presence. Treatment tanks should be kept under diffuse light and away from sunlight during treatment.


    Furan2 is a good combo medication that consist of two nitrofuran antibiotics (nitrofurazone and furazolidone) plus good old methylene blue. That gives it both bacteriostatic and bactericidal properties, and makes it active against various gram-negative and gram-positive bacteria. The methylene blue stains the water in the treatment tank as and prevents the photosensitive nitrofuran antibiotics from being deactivated by light. Methylene blue is effective in preventing fungal growth, and it has antiprotozoal and antibacterial properties as well, by virtue of its ability to bind with cytoplasmic structures within the cell and interfere with oxidation-reduction processes. This makes the combination of methylene blue, nitrofurazone and furazolidone very broad spectrum and fairly potent. Furan2 is especially effective for treating mild skin infections, but serious infections such as vibriosis or marine ulcer disease should be treated with stronger antibiotics, such as doxycycline + kanamycin.

    Best of all, Furan2 can be safely combined with Aquarium Pharmaceuticals antiparasitic medications such as Acriflavine to increase its effectiveness and guard against secondary infections when you are treating for parasites.

    Thus, when combined with a good antiparasitic medication like Acriflavine, a good combination drug like Furan2 can be the ultimate weapon in your medicine cabinet. It is effective against a wide range of diseases, making it a versatile shotgun for restoring order when trouble breaks out in your tank.

    Not all brands of Furan2 include methylene blue, Claire, so if you obtained a Furan2 medication that does not include methylene blue, just add enough methylene blue to the hospital tank yourself drop by drop to turn the water a shade of light to medium blue. The methylene blue will help cure this fin infection if it is fungal in nature or if it is due to certain types of bacteria, but more importantly it will protect the photosensitive acriflavine and Furan2 from the light, helping them to maintain their full efficacy throughout the treatment.

    Methylene blue and formalin should be available from any well-stocked fish store or pet shop, and the larger outlets will also have Furan2 and acriflavine available. If not, they can be obtained from National Fish Pharmaceuticals (aka the Fishy Farmacy) at the following URL:

    if you are unable to obtain the acriflavine and/or Furan2, Claire, there are other medications that may also be effective for this problem you can consider. (Again, I would administer a formalin bath and then release your stallion in the hospital tank for treatment with the other medications.)

    For example, Ampicillex is sometimes effective for treating fin rot as well as fungus and should be available from most local fish stores:

    Ampicillex – the active ingredient in this medication is Ampicillin Trihydrate, which is a synthetic Penicillin, and a superior antibiotic for treatment of fin rot and stubborn eye and mouth infections. Ampicillin also has effective action against many Fungal infections. As with other antibiotics, use every other day for 5 days (3 treatments are recommended). Will not color water.

    Either TMP-sulfa or 4 Sulfa TMP sometimes would also be a very good choice for treating fin rot:

    Trimethoprim and Sulfathiazole Sodium (TMP-Sulfa)

    A potent combination of medications that’s effective in treating both gram-positive and gram-negative bacterial infections. It exerts its anti-microbial effect by blocking two consecutive steps in the biosynthesis of nucleic acids and proteins essential to many bacteria, making it very difficult for bacteria to develop resistance to the medications. TMP-Sulfa may be combined with other sulfa compounds to further increase its efficacy and decrease the chance of resistant strains developing. TMP-Sulfa will knock your biofilter for a loop, so be sure to use it in the hospital tank only.

    These forms of sulfa can be obtained via National Fish Pharmaceuticals at <;.

    In short, Claire, I would recommend administering a formalin bath to your seahorse and then treating him in your hospital tank with the following medications, listed in order of preference:

    1) Acriflavine combined with Furan2 (plus methylene blue, if it is not contained in the Furan2 formulation you obtained);

    2) Ampicillex

    3) either TMP-Sulfa or 4 Sulfa TMP.

    If necessary to resolve the problem, the formalin baths can also be repeated every other day providing the seahorse is in good condition.

    Best of luck clearing up the infection of your stallion’s dorsal fin, Claire.

    Pete Giwojna


    Thank you for the information. I have the hospital tank up and running, now I am off to pick up the necessary medications. I notice this morning that my stallion is looking a bit depressed and his breathing is becoming more laboured, so I’m in a bit of a hurry to get him into treatment.

    Do I just follow the directions on the packages for the Furan 2 and Acriflavine? How will I know if they are working or if I should repeat the Formalin bath in two days?


    Hello again,
    Well, it looks like I won’t be able to get Acriflavine here, so I’m not sure what is better, to treat with just the Furan2 or move to the second choice of Ampicillex? Mind you I don’t know if I can get that here either… I know I can get Furan2 though!


    Pete Giwojna

    Dear Claire:

    For this problem, the combination of the acriflavine + Furan2 should be very effective, but I don’t like using either of the medications by themselves to treat this condition. I would rather that you used the formalin bath followed by a regimen of Ampicillex, rather than using just the Furan2 by itself.

    However, Furan2 is always a good medication for seahorse keepers to keep on hand, so I would go ahead and obtain the Furan2 in any case so that it’s available the next time you might need it, Claire.

    How about the formalin? Were you able to obtain formalin, at least, Claire? And the methylene blue?

    If you cannot obtain the acriflavine to use together with the Furan2, or the Ampicillex, as an alternative, then I would recommend that you try a long-term bath with the formalin alone. Here are the instructions for administering Chordata Formalin 3 for prolonged immersion, Claire:


    (a) Since there is conflicting evidence regarding the safety of formaldehyde to biological (nitrifying) filtration, all long-term bath treatments with Formalin·3 may (at the user’s discretion) be done in a separate hospital or treatment tank.
    (b) Remove granular activated carbon from all filters used on the treatment tank; clean or change the mechanical filter media (i.e., filter floss), and return the filter(s) to service (minus the carbon).
    (c)Make a partial water change of approximately 25%
    (d) Depending upon the condition of the fishes needing treatment (i.e., the severity of the disease, involvement of the gills and the degree of debilitation), the dosage should be varied from 1 to 2 teaspoons per 10 gallons (10 to 20 ppm.) Severely diseased or debilitated fishes should be treated at the lower dosage.
    (e) The treatment may be repeated every 24 hours, by repeating all of the above steps, including the required water changes.
    (f) The dosage may be increased as the condition of the fishes being treated improves.
    (g) If the fishes were removed to a separate tank, the original aquarium or pond should remain devoid of all fishes for a period of at least 4 days to insure all of the remaining infestation has expired.

    In that case, Claire, you should not administer a short-term formalin bath before hand. You would just transfer your male seahorse to the treatment tank and then add the formalin as described above, perform a 25% water change and then re-dosing the formalin each day (i.e., every 24 hours). The formalin alone is effective in treating fin rot and fall infections, so that would be your best option if you cannot obtain both acriflavine + Furan2, or the Ampicillex.

    If you can obtain the Ampicillex, go ahead and use it in your hospital tank after administering a short (30-60 minute) formalin bath according to the instructions in my previous post.

    You will know if additional formalin baths are necessary by examining the thick white line on your seahorses dorsal fin. If it is improving after the first treatment, then further short baths of formalin may not be necessary. If the white light does not look better, then don’t hesitate to repeat the short-term formalin bath every other day.

    Good luck obtaining the medications you need to treat this condition and resolve the problem, Claire!

    Pete Giwojna


    Hello Pete,

    I just returned from shopping and I was only able to obtain Formalin and Furan2, nobody was familiar with Acriflavine, must be a US thing, and no luck finding Ampicillex. So I will go ahead and just do the Formalin in the hospital tank.

    The formalin that I got is Forma-Green from National Fish Pharmaceuticals. Do I still use the directions for the other brand that you posted above?? It just says 2 drops per gallon, nothing about re-dosing…

    Pete Giwojna

    Dear Claire:

    Okay, the FormaGreen is a little different than standard formalin. The FormaGreen is a combination of formalin and malachite green so the directions I’ve provided for you earlier no longer apply. I am not familiar with this particular product, but you should use it according to the directions on the label:


    USE: external fungicide, external protozoacide, and ectoparasites, monogenia (i.e., trematodes), Hirudinea and crustacea (e.g., argulus). Helps to protect wounds from secondary infections. Can be used as a dip or for longer baths according to parts per million.

    DOSAGE: for aquariums, use 2 drops per gallon. Treat one time and leave in the water for 5-7 days. Not for use with scaleless fish.

    In this case, it may be beneficial to use the FormaGreen rather than the ordinary formalin, since the combination of formalin plus malachite green is even more effective in treating fungal problems. So if the thick heavy white band on the dorsal fin of your seahorse does indeed indicate fungal involvement, perhaps as a secondary infection, the FormaGreen should help resolve the problem.

    As the instructions say, you dose the treatment tank only once and then leave the medication in the water for 5-7 days without making any water changes. In your hospital tank, if the water quality indicates that a water change is advisable, do a 100% water change (replace all the water in the hospital tank with fresh saltwater) and then re-dose the FormaGreen (two drops per gallon) and leave it in the water until the seahorse has been treated for a total of 5-7 days.

    Just keep the Furan2 in a cool, dry place in case it is needed at another time.

    Best of luck resolving this problem, Claire!

    Pete Giwojna

    Post edited by: Pete Giwojna, at: 2009/06/20 23:16


    So, I have moved the affected seahorse (Tigger) to the hospital tank, and dosed it with the Forma Green. I am pleased to hear that this mixture may be more effective than plain Formalin. Finally I caught a break in the medication department!! I will have to research exactly which meds are available in Canada so that I know what I have access to… It’s quite frustrating!

    Tigger seems to be doing okay in the hospital tank. He had a small meal before I moved him yesterday and I am just getting ready to give him some breakfast. Hopefully he’s settled enough to eat.

    I will keep you updated on his progress. Thank you for all your advice!


    Pete Giwojna

    Dear Claire:

    Okay, so far, so good.

    Here’s hoping that the FormaGreen is effective in resolving the problem with your stallion’s dorsal fin.

    If your hospital tank is located close enough to the seahorse tank so that he could see his tank mates, that will provide Tigger with some moral support while he is undergoing his treatment. If not, then you might consider using the old mirror trick to boost his spirits while he is in isolation instead.

    The mirror trick simply have always taping a mirror up against the aquarium glass where your pony can get a good look at himself. Seahorses will often interact with their own reflections in the aquarium glass, so having a mirror-image seahorse that moves in response to his own actions can be very reassuring for a single seahorse and perk up the isolated individual dramatically. It’s an effective technique for a situation like yours and can fool the lonely seahorse into thinking he or she is still in the presence of other seahorses.

    Best of luck with the treatments, Claire!


    Time for an update… and some questions…

    Tigger is doing fine in the hospital tank, I set up a mirror last night and he danced in front of it for a few minutes 🙂 This is day three in the FormaGreen treatment. I think his fin is improving a bit, I will try to get a photo later today. What sort of results are to be expected by day seven? There is still some white along the edge of the fin.

    I have been testing the ammonia levels in the tank and it has risen to 0.3 today. Is that high enough to warrant the 100% water change we discussed before? The nitrite and nitrate are both still zero.

    Also, this is the same seahorse that was underweight a while back and you thought it was probably internal parasites. I haven’t been able to treat him for those yet, so I thought now that I have the hospital tank set up I should do that as well. Is it best to wait until he is fully recovered from this fin situation before beginning that treatment? Could the parasites be hampering his health enough to have caused this problem and/or be slowing his healing??

    The medication I found for parasites is made by Aquarium Pharmaceuticals and it is called General Cure… It contains 250mg Mertonidazole and 75mg Praziquantel per package, to be added directly to the aquarium water.

    Thanks Pete!

    Pete Giwojna

    Dear Claire:

    Okay, so far so good. It sounds like you are doing a fine job with the treatments.

    Yes, if possible, I would like to see another photograph of Tigger that shows his dorsal fin clearly so that I can get a better idea of how he is progressing. If the FormaGreen is effective, I would hope to see the white band cleared up by the seventh day of the treatment regimen.

    If the ammonia level is at 0.3 ppm right now, it is only going to continue to rise and you need to continue the treatment for several more days, so this would probably be a good time to perform a complete water change. Prepare the water before hand so that it is adjusted to the same specific gravity and pH as the treatment tank, or use more water from the main tank for the water change, and transfer Tigger to a separate container for safekeeping while you perform the water change.

    If you are using a 20-gallon aquarium for your hospital tank, Claire, it’s perfectly acceptable to refill it with only 10-gallons of clean saltwater providing the lower water level does not disable any filtration you may be using on the treatment tank for water movement. If you only refill it with 10 gallons, when you redose the tank with FormaGreen, just be sure to add the appropriate amount of the medication for 10 gallons rather than a 20-gallon aquarium.

    If the newly mixed saltwater (or clean water from your main tank) is not the same temperature as your treatment tank, float Tigger in a plastic bag for 10 or 15 minutes so that he can adjust to the change in temperature gradually before you release him back in the treatment tank.

    If Tigger is carrying a heavy load of intestinal flagellates or other internal parasites, that could be a factor in why he has developed an infection of his dorsal fin. Anything that debilitates the seahorse can leave it vulnerable to opportunistic infections. A combination of metronidazole and praziquantel should be effective in eliminating such internal parasites, but I would not treat Tigger until he has completed the entire regimen of FormaGreen and you have removed all of the medication.

    These antiparasitic medications can be used directly in the main tank, so you may want to wait until Tigger’s dorsal fin problem has cleared up and he has been transferred back to your display tank with the other seahorses before you use the metronidazole/praziquantel, Claire. That would assure that the rest of your seahorses are also treated for intestinal parasites, which is a good precaution since the other seahorses may also have been exposed to the internal parasites via fecal contamination of frozen Mysis they ingested from the bottom of the tank.

    Best of luck resolving Tigger’s health problems and getting him back to normal again, Claire.

    Pete Giwojna


    Here are a couple of photos, I guess when compared to the ones from a few days ago it does look a lot better. I have been using the dark line through his fin as a marker and it hasn’t gotten into that yet, so I don’t think it’s getting any worse, for sure.



    I will perform a water change tonight!

    Pete Giwojna

    Dear Claire:

    Wow — excellent photographs! Great close-ups of the dorsal fin!

    I agree, Claire — I am seeing considerable improvement after three days of treatment. The heavy, thick white band has largely been eliminated. There is some erosion between the fin rays at the very tip of the dorsal fin, but that sort of fraying is to be expected in cases of fin rot, and the important thing is that the infection appears to have been halted so that the fin erosion is not advancing further down the fin towards the body of the seahorse.

    This is encouraging, Claire — it appears that you detected the fin infection in its early stages and that the FormaGreen is effectively combating the infection. Once the infection has been eliminated, the fin damage typically repairs itself quickly and the fraying will regenerate. Hopefully, Tigger’s dorsal fin will soon be good as new again.

    Best of luck with the remaining treatments, Claire!

    Pete Giwojna


    Hello Pete,

    So a couple of things I wanted to run by you… Tigger seems to be continuing to improve, so at the seven day mark, I should just go ahead and put him back into the main tank with his buddies? The infection should be all cleared up by then?

    Also as far as treating the main tank with the anti-parasitic medication, I would have to remove all invertebrates, is that correct? I have quite a few tiny snails in there that I don’t know if I would be able to get out… I was thinking maybe I could properly cycle the quarantine tank and then move all five seahorses in there for the four days required for treatment, but maybe I should try to get it done ASAP for Tigger’s health?? What do you think?

    Lastly, the female H. Angustus that I mentioned before with the weak snick does not appear to be improving as much as I would like. It has been about a week since I noticed it. She doesn’t really look underweight, so she must be eating something but it is a lot of work for her. Does the metronidazole and/or praziquantel help with that if it is infact a parasitic problem rather than a mechanical injury or strain?? If not, what is the course of treatment you would recommend? Non of the other four seahorses are showing any sign of weak snick…

    Thanks Pete

    Pete Giwojna

    Dear Claire:

    Yes, if the white band along the margin of Tigger’s dorsal fin has cleared up completely after seven days of treatment with the FormaGreen, indicating that the fin infection has been resolved, you can return him to the main tank again. However, if you feel that treating him for internal parasites with the antiparasitics (metronidazole + praziquantel) as soon as possible is advisable, then you may want to perform a 100% water change in the treatment tank to remove all of the FormaGreen, and then treat him with the General Cure (metronidazole + praziquantel) in your hospital tank before you return him with the others…

    Yes, whenever you are using antiparasitic medications it is a good idea to remove any invertebrates that might be sensitive to the medication beforehand. This would include cleaner shrimp, snails, and starfish, for example. If that’s not feasible in your case, Claire, then cycling the hospital tank so that it can safely support the seahorses and then treating your herd in the hospital tank is a sensible approach. Intestinal flagellates cannot survive for any length of time outside of their host, so any internal parasites remaining within the main tank within fecal pellets should die off during the 4-5 days that the seahorses are being treated in the hospital tank. I think treating Tigger with the antiparasitic medications could probably wait until the hospital tank has cycled, but you could always treat him first and then treat the rest of the seahorses later, whichever is more convenient for you.

    Regarding the female with weak snick, Claire, the key to a successful outcome with weak snick and related feeding disorders is keeping the patient eating while the healing takes place. That’s what treatment should concentrate on.

    When these feeding difficulties arise, it’s a good idea to try tempting the affected seahorse with live adult brine shrimp. Seahorses suffering from weak snick induced by an injury may have better luck slurping up smaller, lighter, soft-bodied prey like brine shrimp; if so, that will be enough to keep them going while they heal. You’ll want to enrich the brine shrimp to maximize its nutritional value, and gutloading the shrimp with an enrichment product high in HUFA such as Vibrance is a good way to fortify it beforehand. Brine shrimp are filter feeders that will ingest whatever is suspended in the water with them, so all you need to do is add a pinch or two (or drop or two) of the enrichment formula to a small container of saltwater swarming with brine shrimp at least 30 minutes before you offer the shrimp to your seahorse.

    Some hobbyists dealing with weak snick have had good success in coaxing the affected seahorse to feed by transferring the seahorse to a critter keeper or breeder net or similar enclosure that can hang within the main tank itself, and then adding a generous amount of live adult brine shrimp to the container. Within the enclosure, the affected seahorse does not have to compete with its tankmates for the live food, and it is easy to maintain an adequate feeding density within the confined space so that there is always a big juicy brine shrimp passing within striking distance of the hungry seahorse. Add one or two hitching posts within the critter keeper or breeder net so that your male can anchor in place and wait for a tasty brine shrimp to pass within easy reach, and give him an hour or two within the enclosure to eat him fill of the softbodied adult brine shrimp. You can monitor his progress from a nonthreatening distance away from the tank to see how she is doing. In most cases, the seahorse quickly becomes familiar with the routine of being transferred to the special enclosure at feeding time and associates it with tasty live foods and a full belly — positive reinforcements that make it a very nonthreatening, stress-free procedure for the affected seahorse — and, as a result, it may actually come to look forward to it after a few feedings. You can repeat this feeding process two or three times daily in order to fatten him up again, if your schedule allows.
    <Close quote>

    In short, Claire, if the affected seahorse is not experiencing respiratory distress or any other indications that suggest the problem could be due to protozoan parasites, . then you’re most likely dealing with a muscular strain or mechanical injury, and keeping your female eating by providing her with abundant softbodied adult brine shrimp to slurp up is probably the best approach to this problem.

    In either case, keeping the seahorse feeding or providing her with adequate nourishment is the key to resolving weak snick and other related feeding disorders. Many times the problem will resolve itself over time providing you can keep the seahorse well fed in the meantime. Providing your pony with plenty of softbodied adult brine shrimp that are easy to slurp up and swallow is one way to accomplish this.

    But sometimes the problem progresses to the point where the seahorse cannot even suck up the softbodied adult brine shrimp. When that’s the case, Claire, handfeeding the seahorse instead is often the best approach. By handfeeding in this case I mean holding one entire, intact (whole and unbroken) frozen Mysis that you have carefully thawed in your fingertips and then placing the head end of the Mysid directly in the mouth of the seahorse. Many times the seahorse will simply spit it out again, but often if you can insert the Mysis into the seahorse’s open mouth far enough, it’s feeding instincts will kick in and take over so that the seahorse slurps up the frozen Mysis almost reflexively. That’s a much less stressful and less invasive method of force feeding a seahorse that sometimes works well (especially if the seahorse is accustomed to being hand fed and doesn’t shy away from the aquarist). When this method of force feeding works well, it can be maintained indefinitely to provide the seahorses with good nourishment until it has recovered and can feed normally again on its own.

    For example, even the magnificent seadragons sometimes develop problems with weak snick and similar feeding disorders, and professional aquarists will use this same method to provide their prized dragons with good nourishment until they recover, as discussed below:

    <Open quote>
    Over the years, we have seen mouth problems develop in some of our dragons. Sometimes it’s attributed to injury. Sometimes we don’t know what causes it, but we are often successful in getting them to recover on their own with just supportive feedings until we observe that they are back to catching food normally. Sometimes this can take a long time…as in a month or two of force feedings before they are back to catching enough on their own to sustain themselves.

    Although I have not had experience force feeding ribbon dragons, I have both force fed and tube fed leafy and weedy seadragons. Typically, we force feed numerous frozen mysids to a sick dragon up to 3 times a day. By force feeding, I mean that we very gently place a mysid in the mouth of the animal and then lightly hold a finger in front of it so that it can’t easily spit out the food. Usually they learn pretty quickly that they are getting food this way and start to slurp mysids up as soon as they are put in their mouth. I usually try to get 6-10 mysids in per feeding. It takes good eyesight and a steady hand to make sure you don’t injure their mouth with this method. We have also tube fed using a thick slurry of cyclopeeze or pulverized and moistened pelleted food…usually giving around .3cc per feeding…though it’s dependent on the size of the animal. I think we usually use a 2-3mm french catheter cut down to fit on a small syringe. Again we do this 3 x day. We find that the animals do better with the frequent feedings and usually they go right back to searching for food after being released.

    Teryl Nolan
    Aquarium Supervisor
    SeaWorld Florida
    7007 SeaWorld Drive
    Orlando, Florida 32821
    <close quote>

    If the weak snick is due to protozoan parasites rather than a mechanical injury, then treating the seahorse with metronidazole + praziquantel could prove to be helpful. But it can take weeks for a seahorse to heal from the type of muscular strain and injuries that contribute to weak snick.

    Best of luck with the remaining treatments, Claire! Here’s hoping your seahorses are some good as new again, none the worse for wear.

    Pete Giwojna

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