Dear Fish Face:

Pete Giwojna

Dear Fish Face:

I’m very sorry to hear about the problems your female seahorse is having, FF. If she has one or more kinks in her tail, then it sounds very much like she may have gotten her tail stuck in the intake for your external filter and suffered an injury to her tail as a result.

The fact that she has subsequently stopped using her prehensile tail to cling to convenient hitching posts and is no longer eating is an indication that the injury to her tail has become infected. Seahorses with tail infections act as if their tails are very tender and stop using them to grasp onto objects. That is very typical behavior for seahorses with tail rot or white tail disease, for example, and I suggest treating your female seahorse just as if this was a full-blown case of tail rot.

The tip of the tail is especially prone to infection because blood-oxygen levels are often deficient in the extremities — oxygen tension is lowest in the most distal part of the tail — and the bacteria that are responsible for tail rot prefer a low oxygen environment. Even minor scrapes and injuries to the tail can easily become infected, especially if the seahorses stressed, which impairs its immune system. The seahorse’s tail is prone to scrapes and abrasions as well as injuries such as stings from anemones or bristleworm spicules because it is used to grasp objects and often in contact with the substrate.

In this case, FF, I believe it must have been very stressful for the female seahorse to be stuck up against the intake for your external filter for an extended period of time, and if her tail was injured in the process, it has very likely become infected as a result.

The recommended treatment is to transfer the affected female to your hospital tank so that she can be treated with broad-spectrum antibiotics as soon as possible. If you don’t have a suitable hospital tank or quarantine tank up and running at this time, you can easily set one up as follows:

A hospital tank is usually pretty spartan because the substrate can sometimes interfere with the medications that are used. So most of the time, hospital tanks are bare bottomed and about a 10 gallon tank is typical for a seahorse hospital tank.

This is what I normally advise home hobbyists regarding a suitable hospital tank, FF:

Basic Hospital Tank set up

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 and aeration 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 if need be, 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.

As you can see, hospital tank is pretty easy to set up because it’s not intended to house the seahorses long-term, only while they undergo a treatment regimen that usually lasts 10-14 days.

For filtration, I keep things really simple in a hospital tank, using only foolproof air-operated sponge filters for my dwarf seahorses. Avoid sponge filters with weighted bottoms or other metal components, however, since they will rust when exposed to saltwater. Sooner or later this will cause problems in a marine aquarium (sooner in the small setups that are most suitable for H. zosterae). Select a sponge filter that has no metal parts and is safe for use in saltwater. The proper units will have suction cups to anchor them in place rather than a weighted bottom.

The sponge filters I find that work well are the Oxygen Plus Bio-Filters (models 2, 3, 4, or 5) or the Tetra Brilliant foam filters. They have no metal components, making them completely safe for use in saltwater, and just one of these foam filters will do the job on a tank of 5 gallons or less. They do not have a weighted bottom but are equipped with suction cups instead. Two of the smaller models can be used on larger 25-gallon tank like yours, Lori, but one of the larger models, like the one at the link below, would be sufficient for your 10-gallon aquarium:

Click here: Foam Aquarium Filters: Oxygen Plus Bio-Filter 2

Avoid the Oxygen Plus Bio-filter 6, 11, and the Multi sponge, which all have a weighted bottom (metal), that rusts when exposed to saltwater. If you want more filtration, you’re better off going with two of the smaller suction cup sponge filters rather than any of the models with weighted bottoms. For instance, for a 12 -gallon tank, I’d suggest using two well-established foam filters, one at either end of the tank for the biofiltration.

All you need to operate sponge or foam filters is an inexpensive, diaphragm-operated air pump (whatever is available at a reasonable price from your LFS will do just fine), a length of airline tubing to connect the air pump to the foam filter(s), and a set of air valves (gang valves) to regulate the air flow to the filters. That’s all — nothing to it! The inexpensive Apollo 5 air pumps work great for sponge filters, but whatever air pump you have on hand should certainly do the job.

Cleaning the foam filters is a snap. Simply immerse them in a bucket of saltwater and gently squeeze out the sponge until it’s clean and releases no more sediment or debris. Run a bottlebrush through the inside of the tube, wipe off the outside of the tube, and you’re done. The filter is ready to go back in the aquarium with no impairment at all of the biofiltration. Takes only a couple minutes.

Once you have your female transferred to the hospital tank for treatment, FF, you can try providing her with some of her favorite live foods to coax her to eat (she won’t have to compete with the healthy seahorses for the tasty live treats while she is quarantined).

If live adult brine shrimp (Artemia sp.) are available locally from any pet shops or fish stores, they will do in a pinch. Just be sure to disinfect them by soaking them in freshwater for 5-10 min. before you introduce them to the aquarium.

Gammarus amphipods and suitably small live ghost shrimp are also acceptable, but live marine feeder shrimp would be the best option, since they are irresistible to seahorses and are “feed-and-forget” live foods that will survive indefinitely in the saltwater until they are eaten or removed. Live Mysis (Mysidopsis bahia) and Hawaiian volcano shrimp or red feeder shrimp (Halocaridina rubra) are ideal for this purpose, and are always my preferred choice for perking up the appetite of an ailing seahorse.

With regard to good sources for live foods, you can get Gammarus amphipods (green iron horse feed) and Hawaiian volcano shrimp (red iron horse feed) from Ocean Rider and live Mysis from Sachs Systems Aquaculture. All of these live shrimp are what I’d like to call “feed-and-forget” foods, FF. They are tough, rugged little shrimp that you can toss in your tank with no acclimation whatsoever. They are agile and elusive enough that your filters won’t eat them and the seahorses won’t be able to capture them all right away. Some will hide and evade well enough that your seahorses will still be hunting down the stragglers for the next day or two. Best of all, you can toss a nice batch of them in your aquarium, secure in the knowledge that they won’t perish and pollute it, but thrive and survive as real, live, “catch-me-if-you-can” prey items that seahorses cannot resist. Nothing stimulates a seahorse’s feeding instinct like the frantic movements and evasive maneuvers of natural, living prey.

The Ocean Rider Aquaculture Facility in Hawaii (<>) is a good source for the following live foods but the shipping costs from Hawaii can be considerable:

Green Iron Horse Feed (Gammarus amphipods)
Red Iron Horse Feed or Volcano Shrimp (Halocaridina rubra)

As I mentioned, the live Mysis from Sachs Systems Aquaculture would also be a good choice for live Mysis shrimp. They provide live Mysis in lots ranging anywhere from 100 to 5000 for very reasonable prices which include the cost of priority shipping. For example, you can obtain 200 live Mysidopsis bahia for about $35 from Sachs and your seahorses will love them. Or the or the very smallest (1/4″) of the common shore shrimp (Palaemonetes vulgaris) from Sachs would also be a good choice:


Or the live Mysis or post-larval Feeder Shrimp from Drs. Foster and Smith would also be a good choice for this. You can obtain 100 live Mysidopsis bahia for $33.99 or 100 bite-size Feeder Shrimp for $39.99 from and your seahorses will love them. Just copy the following URL (everything within the angle brackets below), paste it in your web browser, and press the “Entered” key, FF, and it will take you directly to the right webpage:


All of the sources listed above are high-health aquaculture facilities that provide disease free live foods. You can buy be feeder shrimp or live foods in quantity and set up a small holding tank for them so that you can dole them out as live treats for your seahorses whenever it’s convenient.

When it comes to broad-spectrum antibiotics, there are a number of different medications you can consider for treating tail infections, FF. Just remember that infected seahorses should be treated with antibiotics in isolation (otherwise the antibiotics may harm the biofilter in your main tank, creating more problems).

There are a few treatment options to consider. Feeding the seahorses with live shrimp that have been gut-loaded or bio-encapsulated with tetracycline/oxytetracycline or minocycline (Maracyn-Two) sometimes produces good results (Giwojna, Oct. 2003). Furan2 is another good option when the tail rot has been detected early on, in its initial stages, especially if the medication can be administered orally via gutloaded adult brine shrimp.

Tetracycline antibiotics (administered orally only) or immersion in the following antibiotics are known to be effective in treating tail rot and other tail infections: Sulfa 4 TMP, Neosulfex, and Neo3 — all broad-spectrum antibiotics consisting of trimethoprim (TMP) and easier kanamycin kanamyacin and/or neomycin combined with various sulfa compounds to produce a potent synergistic combination of antibacterials — are the antibiotics available to hobbyists that seem to work best for tail rot. Unfortunately, Neosulfex and Neo3 are no longer available, but Sulfa 4 TMP can be purchased online without a prescription from National Fish Pharmaceuticals.

And hobbyists can often achieve similar results by creating their own version of these medications by combining neomycin sulfate and/or kanamycin with various sulfa compounds. One that seems to work well is combining neomycin sulfate with triple sulfa.

Here are the instructions for treating with Neomycin and Triple Sulfa together. Dose the Neomycin at 40mg per gallon and replace what is removed with water changes (so, for 10 gallon hospital tank, add 400mg the first day, then each day following, do a 50% water change and add back 200mg). Continue the Neomycin for 10 days. At the same time that you are treating with the Neomycin, dose the Triple Sulfa according to package instructions but for a full 10 days.

You may be able to get neomycin sulfate and triple sulfa compound at a well-stock LFS. If not, you can obtain both neomycin sulfate powder and triple sulfa powder from National Fish Pharmaceuticals. You can order them online at the following site: <<>>

Kanamycin sulfate used alone or in conjunction with neomycin sulfate would also be an excellent choice for treating tail rot, both of which can be combined safely with triple sulfa.

Kanamycin sulfate powder

USE: Gram-negative bacteria for 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.

Combining the kanamycin with neomycin is often especially effective, because they kanamycin is absorbed well and can therefore attack the infection from the inside out (i.e., internally) whereas the neomycin, which is not absorbed well, attacks the infection area from the outside (i.e., externally).

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.

You can get both kanamycin sulfate and neomycin sulfate from the following vendor:

Click here: Fish Medications

As I mentioned above, tetracycline in oxytetracycline can be effective treatments for tail rot when they are administered orally. However, they are useless as bath treatments for marine fishes. This is because calcium and magnesium bind to tetracycline and oxytetracycline, rendering them inactive (Roy Yanong, US Department of Agriculture). Adding tetracycline or oxytetracycline to saltwater in a hospital tank is therefore completely ineffective (Yanong, USDA), but administering the antibiotics orally can produce good results.

Okay, Fish Face, those are my thoughts on treating your female seahorse for a suspected tail infection. If the problem is so severe she will longer accept live foods either, then you will need to force feed the seahorse to keep her strength up while the antibiotics have a chance to work on the infection. Let me know if force feeding becomes necessary and I can provide you with some guidance in that regard.

Good luck.

Pete Giwojna, Ocean Rider Tech Support

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