At the first sign of an infection could be vibriosis, it’s important to isolate the affected seahorse so that the rest of the herd isn’t exposed to the same pathogens, and to begin treating the seahorse aggressively in isolation with potent broad-spectrum antibiotics immediately for at least 10 days. The medications that are most useful in resolving Vibrio infections are chloramphenicol (i.e., Chloromycetin), which you probably will not be able to obtain, enrofloxin (brand name Baytril), which is another prescription antibiotic that may also be difficult for you to obtain. Of the antibiotics that are readily available to hobbyists, tetracycline or oxytetracycline would be the best (but ONLY if they can be administered orally), or gentamicin (a very potent gram-negative negative antibiotic) would be a good alternative, or a combination of doxycycline + kanamycin can also be effective in treating such infections, all of which can be obtained from National Fish Pharmaceuticals without a prescription.
If you don’t have a suitable hospital tank or quarantine tank up and running at this time, you can set up a makeshift hospital tank as follows:
The Hospital Ward or Quarantine 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.
Here is some additional information regarding marine ulcer disease to give you a better idea of the type of problem I believe you may be dealing with:
MARINE ULCER DISEASE, A.K.A. ULCERATIVE DERMATITIS, A.K.A. HEMORRHAGIC SEPTICEMIA, A.K.A. “FLESH-EATING BACTERIA”
Marine ulcer disease is a particularly nasty type of infection that most hobbyists have come to know as “flesh-eating bacteria,” and indeed it can often be attributed to bacteria, most notably gram-negative Vibrio or Pseudomonas species (Giwojna, Nov. 2003). Vibrio in marine fish is the equivalent of the Aeromonas bacteria that plague freshwater fishes (Dixon 1999; Basleer 2000), causing external hemorrhagic ulcers (bloody lesions). Vibriosis is probably the most common bacterial infection of captive seahorses and one of the most difficult to eradicate from your system. Vibrio bacteria are motile gram negative rods, which measure about 0.5 X 1.5 micrometers (Prescott, 2001). When grown on suitable media they appear as shiny, creamy colored colonies (Prescott, 2001).
Marine ulcer disease or hemorrhagic septicemia can manifest itself in a number of forms. The most common of these are the external hemorrhagic (bloody) ulcers, which appear as localized open wounds on the body (Dixon, 1999). It may be helpful to think of this condition as a form of skin rot. The first symptoms are usually small, discolored areas of skin that often become red and inflamed (Giwojna, Nov. 2003). These may become large bloody spots or lesions (the characteristic ulcers) as the disease progresses, leading to sloughing of the skin and localized swelling (Giwojna, Nov. 2003). (I have found that many times hobbyists have a tendency to dismiss these ulcers as “heater burns,” especially when they appear on the flanks or pouch of the seahorse, and to delay appropriate treatment on the basis of this misdiagnosis. Avoid this all-to-common mistake!) In severe cases, the underlying musculature also becomes infected, and the rapid tissue erosion that can result is one of the most alarming aspects of ulcer disease. At this advanced stage, all too often, the infected fish can longer be saved (Giwojna, Nov. 2003).
Badly infected fishes may develop a distended, fluid-filled abdomen due to internal bacterial infection (septicemia) of the kidneys, liver or intestinal tract (Dixon, 1999). This disrupts the normal circulation of the blood and lymph, causing fluids to accumulate in the intestine and abdominal cavity (Dixon, 1999).
The most dangerous form of hemorrhagic septicemia occurs when the bacteria spread internally and become septic, infecting the blood (Dixon, 1999). The bacteria release toxins into the bloodstream, making it the most virulent of these infections (Dixon, 1999). This insidious form of the disease does not produce the telltale external ulcers, and acute infections can kill quickly with little warning due to the lack of outward signs (Dixon, 1999). Affected fish become listless and lethargic (Dixon, 1999), which may be hard to pick up on with seahorses. Respiration is rapid and seahorses usually darken in color and go off their feed. These behavioral indicators are especially difficult to detect in seahorses due to their lazy lifestyle and habit of changing colors frequently. Seahorses may succumb to the acute form of this disease before the aquarist realizes anything is amiss, and hobbyist often ascribe such mysterious losses to Sudden Death Syndrome.
In seahorses, this disease sometimes takes the form of bilateral edema of the periorbital tissue (Bull and Mitchell, 2002, p19). The eyes themselves are not affected, as in popeye or Exopthalmia; rather, the tissue around both eyes swells up. The eyes are thus unaffected but are encircled by rings of swollen tissue. Hobbyists have described this condition to me by saying that their seahorse had developed “doughnut eyes.” These characteristic doughnut eyes are often accompanied by swelling of the soft tissue around the tube snout (Bull and Mitchell, 2002, p19). Some cases develop this peculiar facial edema as well as the usual skin ulcers and tissue erosion (Bull and Mitchell, 2002, p19).
Hemorrhagic septicemia or marine ulcer disease can be a very stubborn and difficult infection to treat, especially when it is due to Vibrio and the disease is acute or advanced. However, if the condition is detected early and treatment is begun when the discolored patches of skin or other symptoms are first noticed, antibacterial agents are often helpful (Giwojna, Nov. 2003). The professional aquarists treat this disease aggressively, using bivalent Vibrio vaccines, immunostimulants such as a beta-glucan, and injections of antibiotics (Bull and Mitchell, 2002, p19).
Aside from administering beta glucan (a primary ingredient in Vibrance) orally, such measures are beyond the grasp of we home hobbyists. We must make do by treating the affected specimens in isolation using wide spectrum antibiotics such as chloramphenicol, enrofloxin (brand name Baytril), tetracycline antibiotics (i.e., tetracycline or oxytetracycline) if and only if they can be a minister orally, gentamicin sulfate, doxycycline, kanamycin, neomycin sulfate, sulfonamide or streptomycin. In mild cases that are detected early, Furan2 or Nitrofuracin Green can sometimes also be helpful. As with other bacterial infections, lowering the water temperature during the course of treatment can help a great deal. This is your best course of action when you are confident that the problem is due to a bacterial infection, such as Pseudomonas or Vibriosis (Giwojna, Nov. 2003).
Chloramphenicol is the treatment of choice. It can be given orally or used as a bath (Prescott, 2001c). Therapeutic baths lasting 10-20 hours are administered in a chloramphenicol solution consisting of 40 mg per liter of water (Prescott, 2001c). If the seahorse is still eating, the chloramphenicol can also be bioencapsulated by gut loading feeder shrimp or ghost shrimp with flake food soaked in the antibiotic solution. Even if the affected seahorses does not eat, feeding medicated shrimp to its tankmates is a good way to help prevent this contagious disease from spreading to the healthy seahorses (Prescott, 2001c).
All things considered, I would say that chloramphenicol (i.e. Chloromycetin) is the treatment of choice for marine ulcer disease (i.e., flesh-eating bacteria) and most Vibrio infections, in general. It is effective both as a bath for prolonged immersion or when administered orally. If the affected seahorse is no longer eating, then administering the chloramphenicol to the treatment tank would be a good option for you if your other seahorses develop any symptoms of this disease.
The treatment protocol for Chloramphenicol or Chloromycetin is as follows:
Chloramphenicol can be used to treat Vibriosis at 40 mg/ litre of water (which comes out to about 150 milligrams per gallon) in a bath for 10-20 hours. It is important to watch the quality of the water, and if it starts to become turbid, the water must be changed. It is best to treat in a separate tank. In stubborn cases, a series of such baths may be necessary to resolve the problem, in which case a complete water change should be performed before the medication is redosed.
Chloramphenicol can also be used as an additive to the feed, if the fish are still eating (all to often in a major infection they will refuse to eat, but this treatment may be most useful in preventing the horizontal spread of the infection). When used as an addition to the feed use 500 mg per 100 gram of feed. (In the case of seahorses, the flake food medicated with chloramphenicol in this way would first be bio-encapsulated in live feeder shrimp, which would then in turn be fed to the seahorses.)
If you do obtain the chloramphenicol, be sure to be very careful when handling it. Remember, in a few rare individuals exposure to chloramphenicol can cause a potentially fatal side effect (aplastic anemia). These are rare cases and almost always involve patients who were being treated with the medication, but I would use gloves when handling it as a precaution and if you crush crush up tablets of chloramphenicol, be very careful not to inhale any of the power.
Because of this side effect, which affects one in 100,000 humans, chloramphenicol is no longer available as a medication for fishes and can therefore be difficult to obtain.
Baytril is another good antibiotic for treating ulcerative dermatitis and tail rot, but it is a prescription medication that you would need to obtain from your family Vet. It would be your next best option if you cannot obtain the chloramphenicol.
Baytril (Enrofloxacin) is a powerful new broad-spectrum antibiotic that increasingly used to treat infections of the urinary tract, skin, prostate, gastrointestinal system, liver, ears, and lungs in humans. It is affective against both gram-negative and gram-positive bacteria and is widely used in aquaculture to treat marine fish. It belongs to a relatively new class of antibiotics called fluoroquinolones, which are effective against a wide variety of bacteria, and is now being used in the aquaculture industry to treat bacterial infections in valuable fish. In liquid form, enrofloxin (Baytril) can be administered either by injection at around 10mg/kg bodyweight e.o.d. or as a bath at 30ppm for 1 hour daily for 5 days.
The Baytril can also be administered orally by tube feeding it to the seahorse, which is helpful when the seahorse is not eating, but it is a stressful procedure for the seahorse. Here are the instructions for administering the Baytril orally, again courtesy of Ann at the org:
ENROFLOXACIN Oral Dosage and Preparation Instructions
Active Ingredient: Enrofloxacin
Indication: bacterial infection
The following information is based on the most commonly available tablet sizes for Enrofloxacin/Baytril
available in the US and abroad and an average sized seahorse of approximately 10 grams.
Tube feed the seahorse 0.1mg of Enrofloxacin once a day for 10 days.
Day 1 – 10 of Treatment
• Crush 1/4 of a 68mg or 50mg tablet into a fine powder.
• Use a mini-blender or small hand-blender to thoroughly mix the powder with marine water. Mix 1/4 of a
68mg tablet with 85mL of marine water. Mix 1/4 of a 50mg tablet with 62.5mL of marine water.
• Fill a small syringe with 0.5mL of the solution.
• Tube feed the seahorse just as if you were force-feeding the pony to provide nutritional support.
• Throw out the unused Enrofloxacin and marine water solution. You will need to make new solution daily
because Enrofloxacin breaks down quickly in saltwater causing it to become completely ineffective by the
Enrofloxacin is available only by prescription from a veterinarian.
Enrofloxacin International Version – Tablets are produced in 15mg, 50gm, 150mg, & a 2.5% injectable solution
Enrofloxacin US Version – Tablets are produced in 22.7mg, 68mg, 136mg, & a 2.27% injectable solution
If you are able to ascertain the exact weight of your seahorse you may want to adjust the dosage as
necessary to get the most benefit from the medication. In such an instance you would dose Enrofloxacin
at 0.01mg of the medication per gram of body weight.
A veterinarian who works regularly with small exotics will be familiar with the proper way to dilute
injectable Enrofloxacin solution to fit your needs.
If you do not have access to prescription medications such as chloramphenicol or enrofloxacin (Baytril), then you should consider using tetracycline or oxytetracycline instead, since they are readily available to hobbyists, but ONLY if they are administered orally. (The tetracycline antibiotics are useless in saltwater, because calcium and magnesium bind to the medications and deactivate them when the pH is 7.6 or above.) So the only way tetracycline antibiotics can be used effectively with seahorses is to gutload feeder shrimp with the medication or, alternatively, to soak frozen Mysis in the proper concentration of the medication, and then feed the medicated Mysis to the seahorses. Obviously, this is only an option if the affected seahorse is still eating, which is often not the case.
If you can obtain live adult brine shrimp, the feeder shrimp can be gut loaded with the tetracycline antibiotics and then fed to the seahorses. In that case, the best way to administer the tetracycline would be to bioencapsulate it in live adult brine shrimp and then to feed the medicated shrimp to the ailing seahorse.
Many times the most effective way to administer antibiotics orally is by bioencapsulating or gutloading them in live shrimp, which are then fed to the seahorses. The easiest way to gutload antibiotics is to bioencapsulate them in live adult brine shrimp (Artemia spp.), as described below. The recommended dosage of antibiotic for this varies between 100-250 mg per liter or about 400-1000 mg per gallon of water. Stay within that range and you should be all right.
In the case of tetracycline, I recommend using 500 mg per gallon of freshwater for bioencapsulating the antibiotic in adult brine shrimp. Tetracycline is a photosensitive drug, so keep the container of freshwater covered to shield it from the light or in a relatively dark area of the room while you are gutloading the brine shrimp.
If the antibiotic you are using comes in tablet form, crush it into a very fine powder (you may have to use a household blender to get it fine enough) and dissolve it in freshwater at the dosage suggested above. Soak the adult shrimp in freshwater treated with the antibiotic for 15-30 minutes and then feed the medicated shrimp to your seahorses immediately. (Don’t let your pumps and filters “eat” all the brine shrimp!)
The brine shrimp are soaked in freshwater, not saltwater, because in theory the increased osmotic pressure of the freshwater helps the antibiotic solution move into their bodies via osmosis. But in fact nobody knows for sure whether the antibiotic is diffusing into the brine shrimp or they are ingesting it in very fine particles (brine shrimp are filter feeders and will take in whatever is suspended in the water with them) or whether the brine shrimp merely become coated with the antibiotic while they are soaking in it. But that’s not important — all that really matters is that gut-loading adult brine shrimp with medications this way is effective.
The antibiotics I would recommend for gutloading in your case are tetracycline or oxytetracycline. Tetracycline is widely available for aquarium use, so you should easily be able to get a product at your LFS in which the primary ingredient is tetracycline, such as Maracyn-TC by Mardel Labs or Tetracycline MS by Fishvet. These products generally include 250 mg capsules or tablets of tetracycline, or packets of 500 mg tetracycline powder, which would make it easy for you to determine the right amount to add to 1 gallon of freshwater in which to soak your brine shrimp to gutload them with the antibiotic. (Just add two of the 250 mg capsules or crushed up tablets — i.e., 500 mg worth — of the tetracycline to a gallon of water.) Or in the case of the Tetracycline MS, use one 500 mg packet per gallon of freshwater.
Although tetracycline and oxytetracycline generally work very well when administered orally, they are all but useless when used as bath treatments for marine fish. This is because the calcium and magnesium in hard water or saltwater bind to tetracycline and oxytetracycline, rendering them inactive (Yanong, US Dept. of Agriculture). In addition, tetracycline and oxytetracycline are photosensitive drugs and will decompose when exposed to light. So these drugs are very useful for seahorses when they are administered via bioencapsulation, but they are utterly ineffective when added to the water in a saltwater aquarium are hospital tank (Yanong, USDA). This is another reason why you must soak the live adult brine shrimp in freshwater when gutloading them with tetracycline or oxytetracycline.
Gutloading the adult brine shrimp in freshwater has several advantages. First of all, it disinfects the brine shrimp (the osmotic shock in going from concentrated saltwater to freshwater will kill off any protozoan parasites the brine shrimp may have been carrying). Secondly, the freshwater increases the effectiveness of the gutloading process by allowing some of the medication to enter the body of the brine shrimp via osmosis. And gutloading the adult brine shrimp in freshwater saves the hobbyist from having to mix up fresh saltwater every day in order to medicate the adult Artemia. Just use dechlorinated/detoxified freshwater as described above, and everything should go smoothly. But the most important reason that you gutload the adult brine shrimp in freshwater when you are using tetracycline or oxytetracycline is that these medications will be deactivated in saltwater and rendered useless if you attempted to bioencapsulate the medication in adult brine shrimp that are in saltwater.
I would feed your seahorses their fill of adult brine shrimp gutloaded with tetracycline once a day for 7-10 days. Gutload a new portion of the adult brine shrimp each day for the seahorses’ first feeding of the day when they are the most hungry. So that would be a total of 7-10 feedings, one per day, using adult brine shrimp gutloaded with the tetracycline. Give the seahorses a second feeding of frozen Mysis enriched with Vibrance later in the day. The Vibrance includes beta glucan as an active ingredient, which is in an immune stimulant that will help the seahorses to fight off any infections.
It is impossible to determine precisely what dosage of medication each individual fish ingests when gutloading, but the tetracycline antibiotics are very safe and you really cannot overdose a seahorse using this method of treatment. Feeding each seahorse its fill of shrimp gut-loaded with tetracycline for 7-10 days assures that they receive an effective dose of the medication. As long as each seahorse is getting its share of the medicated brine shrimp every day during the treatment period, you needn’t be concerned if one of the ponies is eating more than the others.
If the seahorse is not eating, you can therefore not administer the antibiotics orally, consider treating the pony with gentamicin or a combination of doxycycline + kanamycin, as explained below.
Gentamicin is one of the most potent of all antibiotics against gram-negative bacteria. It is effective when dissolved in saltwater and is readily absorbed into the bloodstream of the fish so it can be used in a hospital tank as follows:
Gentamicin Sulfate Powder 100%
USE: probably the most powerful gram-negative antibacterial on the market today. Effective in fresh and saltwater aquariums. Only a single dose is usually required. One of the few drugs that is absorbed into the bloodstream through the gills.
Dosage: 1/4 teaspoon per 40 gallons. Only one dose is necessary. Treat one time and leave in water for 7-10 days. If water changes are done, replace the medication according to how much water was changed.
(National Fish Pharmaceuticals)
Otherwise, your next best alternative may be to obtain doxycycline and kanamycin from National Fish Pharmaceuticals and use them together to form a synergistic combination of antibiotics that is often very effective in treating Vibrio infections.
USE: broad spectrum antibiotic derived from oxytetracycline. Use for both gram-positive and gram-negative bacterial disorders, including fin and tail rot, septicemia, and mouth rot. Unlike tetracycline antibiotics, it will not be deactivated by the high pH levels found in marine aquaria. Works in a similar manner to chloramphenicol.
DOSAGE: add 1/4 teaspoon per 20 gallons, every 24 hours for 10 days. Do a 25% water change before each treatment.
This is a potent broad-spectrum, gram+/gram- aminogylcoside antibiotic. It is wonderfully effective for aquarium use because it is one of the few antibiotics that dissolves well in saltwater and that is readily absorbed through the skin of the fish. That makes it the treatment of choice for treating many bacterial infections in seahorses. Kanamycin can be combined safely with certain other antibiotics such as doxycycline or neomycin (as well as metronidazole) to further increase its efficacy. Like other gram-negative antibiotics, it will destroy your biofiltration and should be used in a hospital tank only.
USE: gram-negative bacterial infections and resistant forms of piscine tuberculosis (mycobacteria). Works especially well in saltwater aquariums.
DOSAGE: add 1/4 teaspoon per 20 gallons. Treat every 24 hours and perform a 25% water change before each treatment. Treat for 10 days. (When treating piscine tuberculosis, treat for 30 days.)
Both the doxycycline and kanamycin can be obtained online from National Fish Pharmaceuticals at the following URL:
In summation, I would recommend isolating the affected seahorse and treating him aggressively with antibiotics in your hospital tank. The following antibiotics have proven to be effective in treating such infections when they are detected early (I have listed them in order of preference):
Chloramphenicol (i.e., Chloromycetin)
enrofloxin (i.e., Baytril)
tetracycline or oxytetracycline (but only if they can be administered orally)
Doxycycline hydrochloride + kanamycin sulfate
Furan2 (if the dosage and duration are increased and early treatment is possible; preferably administered orally)
In your case, the infection appears to be well advanced and you should avoid using Furan2 or Nitrofuracin green and concentrate on the other antibiotics listed above instead.
Best of luck resolving this problem.
Pete Giwojna, Ocean Rider Tech Support