Noobie owner!

Dear Mike:

I’m sorry to hear about the problems that your male seahorse has developed recently. It’s difficult to say why he may have become so lethargic, spending much of the time laying on the bottom of the aquarium, but I would be happy to share my thoughts on the matter with you.

Sometimes that sort of behavior is an indication of a problem with negative buoyancy, which can result from either an underinflated swimbladder or a buildup of fluid in the abdominal cavity. But if your male is able to swim normally and perch upright when he wants to, and is behaving normally otherwise, then I don’t think his behavior is due to negative buoyancy. If not — if his swimming is also affected and he has a tendency to sink — please let me know right away and I will advise you on the appropriate treatments for a seahorse that’s suffering from negative buoyancy.

Laying on the bottom for extended periods can also be a sign of generalized weakness in the seahorse. In that case, the seahorses lack the energy to swim normally and hold themselves up right in their normal posture. You will sometimes see that sort of behavior in seahorses that are badly malnourished or that are oxygen deprived. But if your seahorse is eating well and doesn’t have that pinched in abdomen that is so typical of a seahorse that’s not getting enough to eat, then it seems unlikely that he is lying prone like that because he has too weak to maintain his normal posture.

You might consider adding one or more airstones anchored just beneath the surface of the tank to increase the surface agitation and aeration, thereby promoting better gas exchange at the air/surface interface and improving the oxygenation of the aquarium water.

Extreme lethargy, laying on the bottom, loss of coordination, and loss of appetite are also seen in cases of accidental poisoning, so that’s another possibility you should keep in mind, as discussed below:

Accidental Poisoning & Environmental Diseases Associated with Water Quality

Ammonia poisoning and nitrite toxicity are the most common of these problems (Indiviglio, 2002). Ammonia is highly toxic to fish and invertebrates in even small amounts (> 0.01 mg/L or ppm). Nitrite is slightly less poisonous to fishes, but deadly to many invertebrates at very small concentrations (0.01 mg/L or ppm). To be safe, ammonia and nitrite levels must be kept at zero at all times.

Dangerous levels of ammonia and nitrite can build up in the aquarium for many reasons. Failure to cycle the tank properly and establish the biofilter is a common beginner’s mistake, as is adding too many specimens too soon before the biofilter can adjust to the heavier bioload (i.e., new tank syndrome). Impairment of the biofiltration can also cause ammonia and nitrites to reach dangerous levels. This can result from medicating the main tank, a lack of oxygen for the beneficial aerobic bacteria due to a pump failure or power outage, disrupting the live sand bed too deeply when cleaning the substrate, and so on. The undetected death of tankmate such as a starfish or large snail can lead to harmful ammonia and/or nitrite spikes, as can overcrowding and overfeeding.

Seahorses suffering from ammonia and/or nitrite poisoning will struggle to breathe. They will be lethargic and exhibit rapid respiration. They may appear disoriented, periodically detaching from their hitching posts only to sink to the bottom (Indiviglio, 2002). Test kits will confirm your diagnosis by revealing unacceptable levels of ammonia and/or nitrite in the water.

The appropriate treatment is to immediately transfer the seahorses to clean saltwater in a hospital tank and add methylene blue, which aids oxygen transport in the blood. Methylene blue will help seahorses with ammonia poisoning to breathe, and can actually reverse the effects of nitrite toxicity. While the seahorses are undergoing treatment, partial water changes will reduce the levels of ammonia/nitrite in the main tank. The cause of the problem must then be determined or corrected. This can be as quick and easy as finding and removing a dead specimen or as difficult and time consuming as recycling the entire tank.

Heavy metal poisoning is another environmental disease hobbyists must sometimes contend with. Even tiny concentrations of heavy metals are deadly to marine fish and invertebrates. This used to be a common cause for concern among marine aquarists when steel-framed aquariums were commonplace, but the advent of all-glass tanks and acrylic aquaria have greatly reduced such problems.

The chief offender nowadays is copper, which usually becomes a problem when the hobbyist overdoses the tank with a copper-based medication (Indiviglio, 2002). Other times copper enters the aquarium in tap water used for water changes or topping off the tank. The copper is leached into the tap water from copper pipes and plumbing (Indiviglio, 2002).

Other heavy metals (iron, lead, and aluminum) sometimes also present a problem when they are accidentally introduced to the aquarium in rocks, gravel, ornaments or decorations. Some of rocks and gravel sold (e.g., red flint) for freshwater use are unsafe in marine tanks because of a high metal content. The same is true for many aquarium ornaments and decorations (Giwojna, 1990). Be especially wary when purchasing artificial plastic plants for the aquarium. Stick with calcareous rocks and gravel and make certain any ornaments or plastic plants you consider are designed for use in marine aquariums and certified to be safe.

Even the popular sponge or foam filters are often a hazard. Many of them contain metal weights as ballast to hold them on the bottom, which is fine in freshwater but can be deadly in a saltwater setup when the metal slugs corrode and leach heavy metal ions into the water.

Seahorses suffering from heavy metal poisoning will act as if they are falling-down drunk. They will be listless and loggy, and if they attempt to move, they will be disoriented, bump blindly into things, and have great difficulty maintaining their normal equilibrium and balance (Giwojna, 1990). And they will be breathing hard and fast.

Treatment is as for ammonia/nitrite poisoning — get them into clean saltwater ASAP, identify the source of contamination and eliminate it, and change out the water in the main tank. Polyfilter pads pull out copper and many heavy metals and may be especially useful in such a situation.

Contamination of the aquarium water with household chemicals is another common problem for the hobbyist (Indiviglio, 2002). Avoid using anything that gives off strong fumes anywhere near your aquarium! This includes bleach, paint, lacquer, varnish, paint thinner, turpentine, insect sprays, bug bombs, pesticides, hairy spray, cigarette smoke, and household cleaners of all kinds (Giwojna, 1990). Even if the aquarium is tightly covered or sealed with plastic, airborne contaminants from fumes and aerosols will still be pumped into the aquarium from the air pumps (Indiviglio, 2002). To prevent this from happening when you must use such products near an aquarium that cannot be moved, disconnect the air pumps first and work only in well-ventilated area. Use submersible powerheads to maintain circulation in the covered aquarium, work fast, and air out the room thoroughly before you reconnect the air supply.

Medicating the aquarium is the worst possible thing you can do when seahorses are suffering from diseases related to water quality or environmental problems such as the toxic conditions described above (Giwojna, 1990). Afflictions such as these are not caused by parasites or pathogens, so medicating the tank not only fails to address the problem, it actually makes matters worse (Giwojna, 1990). Chemotherapeutic agents can be harsh on the seahorses, especially when they are already weakened due to poor water quality or actual poisoning. Worse yet, they are often hard on the biofilter as well and apt to further degrade water quality by killing off beneficial Nitrobacter and Nitrosomonas bacteria.

Therefore, when accidental poisoning may have occurred, a series of water changes combined with activated carbon filtration and the use of Poly-Filter pads is the best treatment option. For best results, the seahorses should be transferred to another aquarium with fresh seawater while the water is completely replaced in the main tank.

A bare-bottomed, 10-gallon aquarium with plenty of hitching posts will suffice for a 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 wont 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 10-gallon 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 redose with the medication according to directions after each water change.

Often the hospital tank is filled with water from the main tank, eliminating the need to match aquarium parameters. But that’s not advisable in the case of suspected poisoning, where the water itself may be bad. In that case, you fill the hospital tank with freshly mixed seawater and use your hydrometer to adjust it to the proper salinity or specific gravity by adding more salt mix or more freshwater as the case may be. A pH test kit can verify that the pH is the same as in your main tank. If not, the pH can be adjusted upwards or downward in the hospital tank using commercially made products that are available at any LFS. Or if you want to raise the pH, you can use ordinary baking soda (sodium bicarbonate) to gradually increase the pH.

Here are the instructions for performing the very brief dip in methylene blue if you’re lethargic male is exhibiting any signs of respiratory distress:

Methylene blue helps hemoglopin transport oxygen to restore normal breathing and can also help control fungus and protozoan parasites as well as certain bacteria by virtue of its ability to bind to cytoplasmic structures within their cells.

Commonly known as "meth blue" or simply "blue," this is a wonderful medication for reversing the toxic effects of ammonia and nitrite poisoning. Methylene blue transports oxygen and aids breathing. It facilitates oxygen transport, helping fish breathe more easily by converting methemoglobin to hemoglobin — the normal oxygen carrying component of fish blood, thus allowing more oxygen to be carried through the bloodstream. This makes it very useful for treating gill infections, low oxygen levels, or anytime your seahorses are breathing rapidly and experiencing respiratory distress. It is the drug of choice for treating hypoxic emergencies of any kind with your fish. However, methylene blue will destroy nitrifying bacteria so it should be used in a hospital tank or as a brief bath or dip only (if used in an established aquarium, it will impair the biological filtration and the tank may need to be cycled all over again).

If you can obtain the Kordon brand of Methylene Blue (available at most well-stocked local fish stores), there are instructions for administering it as a very brief, concentrated dip are as follows:

For use as a dip for treatment of fungus or external parasitic protozoans and cyanide poisoning:
(a) Prepare a nonmetallic container of sufficient size to contain the fish to be treated by adding water similar to the original aquarium.
(b) Add 5 teaspoons (24.65 ml) per 3 gallons of water. This produces a concentration of 50 ppm. It is not recommended that the concentration be increased beyond 50 ppm.
(c) Place fishes to be treated in this solution for no longer than 10 seconds.
(d) Return fish to original aquarium.

When you administer such a dip, hold the seahorse in your hand throughout the procedure and time it closely so that the dip does not exceed 10 seconds.

So you might consider performing a series of water changes and adding a polyfilter pad and/or a good brand of activated carbon to your seahorse tank in case the water may have been contaminated accidentally. If the seahorse is experiencing any signs of respiratory distress (rapid respiration, huffing, or labored breathing), then a brief dip in methylene blue may be helpful.

Other than that, about all I can suggest is to keep a close eye on your male for any other signs of a problem, make sure he is getting plenty of enriched frozen Mysis to eat, and be sure to keep the dissolved oxygen levels in your seahorse tank high.

Best of luck with your lethargic male seahorse, Mike. Here’s hoping he’s sown feeling like himself again, actively swimming and exploring his surroundings.

Respectfully,
Pete Giwojna