Re:disease question

Pete Giwojna

Dear Pat:

I’m happy to hear that your Mustangs and Sunburst are doing so well!

However, judging from the symptoms you describe, it sounds like your original pair of erectus have developed 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:"

<Close 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 damage since 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>

Fin rot is not normally highly infectious, so it should not be necessary to treat the entire tank. Nowadays, of course, we have much better treatments at were available in Mildred Bellamy 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. For example, TMP-sulfa or 4 Sulfa TMP sometimes work wonders in cases of 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

However, in your case, Pat, since the tail of your female also seems to be involved, I would recommend a more aggressive combination of antibiotics. I suggest you treat the affected seahorses in isolation using a potent combination of antibiotics and gradually reduce the water temperature in your hospital tank to as low as 68°F if possible in order to help get the infection under control.

The medications I recommend for this are aminoglycoside antibiotics (either kanamycin sulfate or neomycin sulfate, or better yet — both of them) combined with triple sulfa or other sulfa compounds:

Kanamycin sulfate powder

USE: Gram-negative bacteria and resistant strains of piscine tuberculosis and other bacterial infections. Works especially well in salt water aquariums.

DOSAGE 1/4 teaspoon per 20 gallons of water. Treat every 24 hours with a 25% water change before each treatment. Treat for 10 days. For piscine tuberculosis, use for up to 30 days.

This is a potent broad-spectrum, gram+/gram- 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 neomycin to further increase its
efficacy. Like other gram-negative antibiotics, it will destroy your
biofiltration and should be used in a hospital tank only.

For best results, it’s an excellent idea to combine the kanamycin with neomycin to further boost its efficacy, as described below:

Neomycin sulfate powder

USE: Gram-negative bacteria (Pseudomonas), piscine tuberculosis and other bacterial infections. Works well in freshwater or saltwater aquariums.

DOSAGE 1/4 teaspoon per 10 gallons of water. Treat every 24 hours with a 25% water change before each treatment. Treat for 10 days. For piscine tuberculosis, use for up to 30 days.

Neomycin is a very potent gram-negative antibiotic. Most of
infections that plague marine fish are gram-negative, so neomycin
sulfate can be a wonder drug for seahorses (Burns, 2002). As
mentioned above, it can even be combined with other medications such
as kanamycin or nifurpirinol for increased efficacy. For example,
kanamycin/neomycin is tremendous for treating bacterial infections,
while nifurpirinol/neomycin makes a combination that packs a heckuva
wallop for treating mixed bacterial/fungal infections or problems of
unknown nature. Keep it on hand at all times.

Neomycin will destroy beneficial bacteria and disrupt your biological
filtration, so be sure to administer the drug in a hospital tank.

If you obtained neomycin in capsule or tablet form rather than the powder, the standard treatment protocol is 250 mg/gal (66 mg/L) as the initial dose and 50% replacement (125 mg/gallon) thereafter with a daily 50% water change repeated for 10 days.

Kanamycin and/or neomycin sulfate can also be combined with various sulfa compounds. One that seems to work well is combining neomycin sulfate with triple sulfa. You may be able to get neomycin sulfate and triple sulfa compound at a well-stocked LFS. If not, you can obtain both neomycin sulfate powder and triple sulfa powder from National Aquarium Pharmaceuticals.

In addition, Pat, you might consider treating the the white spot on the tail of your female with Biobandage as a first-aid miniature. This is a combination of neomycin, a vitamin complex, and unique polymers that form a sort of "biological bandage" that binds the medications to the wound, thus helping to prevent infection and promote rapid healing. It can be obtained online from the following vendor:

It sounds like you’re 26-gallon aquarium may be getting a little overcrowded, Pat, and I suspect that may be one reason why you have had an outbreak of fin rot. The recommended stocking density for Mustangs and Sunburst (Hippocampus erectus) is one pair per 10 gallons, so if you’re 26-gallon tank is now housing three pairs of mature H. erectus, it is officially overstocked. That’s a situation you’ll need to keep an eye on once you resolve the fin rot.

There is a good disease book on seahorses that you may also find very informative, Pat. Dr. Martin Belli, Marc Lamont, Keith Gentry, and Clare Driscoll have done a terrific job putting together "Working Notes: A Guide to the Diseases of Seahorses." Hobbyists will find the detailed information it contains on seahorse anatomy, the latest disease diagnosis and treatment protocols, and quarantine procedures to be extremely useful and helpful. It has some excellent dissection and necropsy photos as well as a number of photos of seahorses with various health problems. This is one book every seahorse keeper should have in his or her fish-room medicine cabinet, and I highly recommend it! In time of need, it can be a real life saver for your seahorses. It’s available online at the following web site:

Best of luck clearing up a fin rot, Pat!

Pete Giwojna

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