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

Pictures of affected fin

  • This topic has 1 reply, 2 voices, and was last updated 15 years ago by Pete Giwojna.
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  • #1702

    Hopefully these will show up okay. I am surprised by how thick and heavy the white line is on his fin!



    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

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