Dear Discus:

Pete Giwojna

Dear Discus:

I’m very sorry to hear that a number of your seahorses have developed a problem with tail rot. That’s a very serious condition that is very often fatal if untreated. Unfortunately, tail rot is highly contagious, and it can spread through an entire herd of seahorses when confined in an aquarium.

The first thing you should do is isolate the healthy seahorses and quarantine the seahorses that have developed tail rot in order to try to stop the spread of this disease. Tail rot is often associated with a spike in water temperatures, so it can also be helpful to gradually reduce your water temperature as much as possible.

I would treat this condition aggressively, Discus, as explained in more detail below:

I recommend a three-pronged treatment procedure for treating cases of white tail disease or tail rot: (1) broad-spectrum antibiotics added directly to the aquarium water to combat the infection externally, (2) oral antibiotics to combat the infection internally, and (3) topical treatments of the affected area.

The topical treatments should be attempted only if the seahorse is strong enough to withstand handling and tolerates the application of the topical medications well. Otherwise, the stress associated with handling the seahorse to administer the topical treatments can do more harm than good.

The topical treatment I find to be most helpful, especially when the tail rot has been detected in the early stages, is Debride Medicated Ointment, which can be especially beneficial when there has been tissue erosion or an open sore has developed.

Debride Medicated Ointment may be useful as a topical treatment for marine ulcer disease, tail rot or snout rot. It contains corticosteroids to reduce swelling and a local anesthetic to reduce pain and tenderness, as explained below in greater detail.

Debride Medicated Ointment

Debride is a medicated ointment that promotes prompt and complete healing of ulcers, mouth rot, fin rot, and tail rot, all symptoms of Aeromonas and Pseudomonas. Koi Care Kennel conducted extensive field trials on this product in 2001. We sent samples of Debride to over 100 hobbyist and dealers who had requested these samples and who had sick fish. The user’s evaluation came back at a 90% success rate.

Debride is safe to apply to the fish’s mouth and will not harm the gills. Debride contains Corticosteroide and topical anesthetic in a butylester copolymer Petroleum distillate carrier. Debride comes in two sizes, a 12 gram tube for approx. 20 applications and a 1 oz. (28.3 grams) tube for approx. 45 applications.

Suggested Retail Price: 12 gram tube $25.95 , 1 oz. (28.3 gram) $44.95

For best results, I would also recommend treating your seahorse with a good antiparasitic that is administered orally (by pretreating frozen Mysis with the meds). The reason for this is that tail rot is often the result of a mixed infection involving ciliates (certain protozoan parasites) as well as a bacterial or fungal infection. I recommend Seachem Metronidazole combined with Seachem Focus and Seachem Garlic Guard for this purpose, as discussed below:

Medicate your seahorses’ frozen Mysis with a good antiparasitic (Seachem Metronidazole) used together with an antibiotic (Seachem Focus) and then soak the medicated Mysis in Seachem Garlic Guard, which acts as an appetite stimulant. Your seahorses will ingest the medicated frozen Mysis and receive protection from potential bacterial and parasitic infections this way, which are possible contributing factors in any tail rot infection. The following information will explain how to use these products (Seachem Metronidazole, Seachem Focus, and Seachem Garlic Guard) properly to medicate the frozen Mysis.

Seachem Metronidazole Aquarium Fish Medication – 100 g

Product Description:
Parasitic and Bacterial infections don’t stand a chance with Metronidazole. When you find your fish infected with such nasty bugs as Ich or Hexamita, grab the Metronidazole and say goodbye to infection. This fast and effective treatment is safe for biological filtration and is easily removed with carbon after treatment. For freshwater or marine fish.


Do not use UV, ozone or chemical filtration during use.
Use 1-2 measures (each about 100 mg each) for each 10 gallons. Measurer included. Repeat every 2 days until symptoms disappear.

To feed, blend 1 measure with about 1 tablespoon of frozen food paste.

Okay, that’s the rundown on the Seachem Metronidazole, which comes in powder form and includes a little scoop for measuring the doses.

And here is the corresponding information for the Seachem Focus, which also comes in powder form with its own measuring scoop:

Seachem Laboratories Focus – 5 Grams Information

Focus ™ is an antibacterial polymer for internal infections of fish. It may be used alone or mixed with other medications to make them palatable to fish and greatly reduce the loss of medications to the water through diffusion. It can deliver any medication internally by binding the medication to its polymer structure. The advantage is that the fish can be medicated without treating the entire aquarium with medication. Fish find Focus™ appetizing and it may be fed to fish directly or mixed with frozen foods. Focus™ contains nitrofurantoin for internal bacterial infections. Marine and freshwater use. 5 gram container.

Types of Infections Treated:


DIRECTIONS: Use alone or in combination with medication of your choice in a 5:1 ratio by volume. Feed directly or blend with fresh or frozen food. Feed as usual, but no more than fish will consume. Use at every feeding for at least five days or until symptoms clear up.

Contains polymer bound nitrofurantoin.

Active ingredient: polymer bound nitrofurantoin (0.1%). This product is not a feed and
should not be fed directly. Its intended application is to assist in finding medications to fish food.

That’s the rundown on the Seachem Focus.

Here is the corresponding information for the Seachem Garlic Guard (pay special attention to the “Directions for Use,” which explains how to use the Garlic Guard together with Seachem Metronidazole and Seachem Focus properly):

Seachem Garlic Guard

* For fresh and saltwater fish, planted and reef aquariums
* Contains allicin, the active ingredient in garlic
* Contains ViSaran C for enhanced health benefits

Whet your fishes’ appetite with the natural healthful properties of garlic. Contains allicin, the active ingredient in garlic with powerful antioxidant properties that can lessen free radical damage to cells – plus ViSaran C for enhanced health benefits. For fresh and saltwater fish, planted and reef aquariums.

Directions for Use: Shake well before use. Soak food in Garlic Guard before feeding. For enhanced effectiveness against Ich and other parasites use Seachem’s Focus and Metronidazole as follows: Add 1 measure of Metronidazole to 1 measure of Focus per tablespoon of frozen food. Completely soak this food mix in Garlic Guard, refrigerate, and feed once or twice daily for 1-2 weeks.

Guaranteed Analysis
Garlic Extract 9900 ppm
Allicin 130 ppm
(active ingredient)
ViSaran C 1000 ppm

Okay, as you can see from the information above, it is actually quite easy to medicate the seahorse’s frozen Mysis using these products: You just use one scoop of the Seachem Metronidazole together with one scoop of the Seachem Focus for each tablespoon of the frozen Mysis you will be medicating, and then thoroughly soak the resulting mixture in Seachem Garlic Guard. The medicated frozen Mysis and then be fed directly to the seahorses and any excess can be frozen for later use.

Feed the affected seahorse(s) twice a day using Mysis that you have medicated as explained above for at least five straight days and that will help the healing process.

The metronidazole will eliminate any protozoan parasites that may be contributing to this tail problem, while the nitrofuran antibiotic in the Seachem Focus helps to combat secondary infections after being absorbed into the bloodstream from the seahorse’s gut. This will allow you to fight infection internally at the same time the neomycin sulfate and sulfa drugs in the aquarium water are combating the infection externally.

Call around to your local pet shops and fish stores to find one who carries products from Seachem Laboratories, and they should have all of the products above. If not, they are all readily available online from many different sources.

Finally, here are some of the antibiotics that have been found to be effective in treating tail rot in some cases that you can consider adding directly to the water in your hospital tank or quarantine tank with the effected seahorses, Discus:

Enrofloxin (brand name Baytril) — a potent prescription antibiotic that can be difficult for the home hobbyists to obtain;

Tetracycline or oxytetracycline (but ONLY when administered orally);

Minocycline (e.g., Maracyn-Two Powder Saltwater by Mardel or a combination of MarOxy + Maracyn-Two);

Sulfa 4 TMP (four different sulfas plus trimethoprim) — National Fish Pharmaceuticals;

TMP Sulfa (trimethoprim and sulfathiazole sodium) — Maracyn Plus by Mardel; National Fish Pharmaceuticals;

Neosulfex or Neo3 (neomycin + sulfa antibiotics) — unfortunately, no longer available

Neomycin sulfate + triple sulfa (both available from National Fish Pharmaceuticals)

Kanamycin sulfate + triple sulfa (both available from National Fish Pharmaceuticals)


Okay, Discus, that’s the rundown on the antibiotics that may be most useful for treating the tail problems your seahorses have developed.

In addition, I am going to attach a document devoted to the subject of Tail Rot in seahorses to an e-mail and send it to you electronically so that you can download the document, save it on your computer, and read to the information as soon as possible. The document is a file that is far too large to be posted on this forum, and I think you’ll find it to be helpful.

Best of luck treating the stubborn tail infections that are plaguing your herd seahorses and returning them to good health again.

Pete Giwojna, Ocean Rider Tech Support

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