Re:my seahorse could have parasites

Pete Giwojna

Dear Tamy:

Rapid respirations or respiratory distress can indeed be one early indication of a parasite problem such as gill flukes or protozoan parasites (ciliates) that invade the gills, but I would expect to see some additional symptoms if you were dealing with an outbreak of such ectoparasites. For example, the irritation from such parasites usually causes the affected seahorse to do a lot of scratching and itching. You will see them rubbing up against objects in the aquarium or reaching up to scratch themselves using their tails, and it doesn’t sound as if your pony is exhibiting any of those behaviors.

So I am thinking that the rapid respirations may be due to low levels of dissolved oxygen in your aquarium, rather than an outbreak of parasites. When the dissolved oxygen levels in the aquarium water are too low and/or the levels of dissolved carbon dioxide are too high, seahorses will naturally become less active and lethargic, and inadequate levels of dissolved oxygen will also put seahorses off their feed, causing a loss of appetite.

Seahorses are especially susceptible to low oxygen levels for a few different reasons, Tamy. For one thing, they have relatively primitive tufted gills that are not as efficient at extracting oxygen from the water as other fishes that have developed gill books. Secondly, seahorse tanks are often poorly circulated because the water currents must be relatively gentle so that they don’t overwhelm the seahorses, which are not powerful swimmers. Finally, because seahorses require vertical swimming space in order to mate comfortably and because the increasing hydrostatic pressure in deeper tanks is protective against gas bubble syndrome, many seahorse keepers favor tall tanks, and the vertically oriented aquariums have very limited surface area for gas exchange. So let’s take a moment to discuss these factors in a little more detail below and then explain how to adjust the conditions in your seahorse tank to overcome these potential problems.

Many seahorse keepers are overly conscious of the inactive life style and limited swimming ability of Hippocampus, and have adjusted their flow rates accordingly, resulting in undercirculated tanks with too little water movement. That’s a serious mistake for a small, close-system aquarium.

Likewise, because the height of the aquarium is an important consideration for a seahorse tank in order to allow the seahorses to mate comfortably during the copulatory rise and to protect them against depth-related conditions such as gas bubble syndrome, many seahorse keepers opt for tall hexagonal or column tanks rather than the usual rectangular aquarium setups. That’s just fine and hex tanks and column tanks can work very well for seahorses providing they are large enough and the aquarist is careful to provide them with good surface agitation in order to assure good oxygenation.

That’s important, because the amount of dissolved oxygen in an aquarium is dependent primarily on three factors: the surface area of the tank, the water circulation in the aquarium, and the amount of surface agitation in the tank. Gas exchange takes place only at the air/water interface or surface of the aquarium, which is where clean oxygen enters the aquarium water and dissolved carbon dioxide is off-gassed, leaving the aquarium. The greater the surface area of the aquarium, the more efficient this gas exchange will be, and the higher the dissolved oxygen levels and the lower the dissolved CO2 levels will be as a result. Likewise, good circulation throughout the aquarium will prevent dead pockets or stagnant areas, assuring that all the water in the aquarium passes over the surface for gas exchange on a regular basis. Surface agitation is important because no gas exchange can take place unless the surface tension of the water is broken. Therefore, the better the surface agitation, the more efficient gas exchange becomes and the better the aquarium will be oxygenated.

This is where hexagonal tanks and column takes are at a disadvantage. The surface area of such tanks is restricted, much reduced from the surface area of a standard rectangular tank of equal water volume. Hex tanks and column tanks thus have less surface area for gas exchange to take place, and it is very important for such tanks to have good aeration and surface agitation to compensate for this drawback. This is especially vital for the seahorse keeper, because our seagoing stallions are very vulnerable to low levels of dissolved oxygen (and high levels of dissolved carbon dioxide) because of their primitive gills structure. So if you will be using a hexagonal aquarium or column design for your seahorse tank, it’s especially important to you to provide good water circulation and surface agitation.

Employing wave makers, devices that automatically alternate the direction of the water flow, and using small powerheads to supplement water movement are all the more important when you are using a tall column tank or hexagonal aquarium. Ordinary airstones and bubble wands can also be helpful for providing surface agitation and improving water circulation, and they will do your seahorses no harm whatsoever as long as they produce relatively coarse bubbles and are positioned where the bubbles cannot be drawn into the intake for the water pumps or filters. Just keep the airstones, air bars, or bubble wands relatively shallow in tall tanks – no more than 20-30 inches deep, and they will help to maintain high dissolved oxygen levels while helping to prevent gas supersaturation.

Improving the water circulation and surface agitation to increase the oxygenation will raise the levels of dissolved oxygen in the aquarium while eliminating excess CO2 via more efficient offgassing. You may notice that your seahorses become more active and have a better appetite, eating more aggressively, as a result, and elevating the levels of dissolved oxygen and reducing the levels of dissolved CO2 will also help to raise and stabilize the pH of the aquarium at the same time. This is important because the pH of the aquarium tends to drop over time, and low pH can be a contributing factor for gas bubble syndrome.

Providing good water circulation and surface agitation to improve the oxygenation and promote more efficient offgassing at the air/water interface is especially important for seahorses because of their primitive gills. Unlike most teleost (bony) fishes, which have their gills arranged in sheaves like the pages of a book, seahorses have rudimentary gill arches with small powder-puff type gill filaments. Seahorses are said to have "tufted" gills because they appear to be hemispherical clumps of tissue on stems. Their unique, lobed gill filaments (lophobranchs) are arranged in grape-like clusters and have fewer lamellae than other teleost fishes. Because of the difference in the structure and efficiency of their gills, seahorse are unusually vulnerable to hypoxia when CO2 levels are high and/or O2 levels are low, so the diligent seahorse keeper will take full advantage of the measures we have discussed above to improve the dissolved oxygen levels in the aquarium.

The point is that, as long as slack-water retreats are available, the greater seahorses can tolerate far more current than most folks suspect and good circulation is as important for a seahorse setup as any other aquarium. What seahorses lack as swimmers is not agility, but rather stamina (Evans, 1998). They can hold their own against strong currents, but not indefinitely, so low flow areas where they can move out of the current and hold when they want to rest must be provided in addition to good circulation.

In short, if your filtration is not turning over the entire volume of the aquarium a MINIMUM of 5 times per hour, your seahorse setup is undercirculated. With a spray bar return raised above the surface of the water to diffuse the outflow, you can safely achieved much higher turnover rates (> 10 times per hour) without producing too much turbulence or current for seahorses in a tall tank. A waterfall return is another good way to diffuse the output from your filter, and also works well for seahorses. There will be an area of relatively vigorous water movement at one end of the aquarium underneath and nearby the waterfall, while the other end of the tank is a relatively low flow area.

Okay, Tamy, that’s the quick rundown on why it’s so important to maintain good surface agitation and water circulation throughout your seahorse tank in order to maintain high levels of dissolved oxygen and low levels of dissolved carbon dioxide. I don’t know if any of these issues are a problem in your particular seahorse setup, but before you consider treating your seahorses for ectoparasites, it would be a good idea for you to try increasing the surface agitation and aeration in your aquarium to promote better oxygenation and to facilitate better gas exchange at the air/water interface. With a little luck, that may be almost necessary to resolve your seahorse’s rapid breathing and lethargic behavior.

If not – if improved surface agitation and better oxygenation does not seem to help or make any difference – then it may be time to consider dipping your seahorse or administering a therapeutic baths that. The most effective bath or dip for you to administer will depend on what medications you have on hand or that you can obtain from your local fish stores, Tamy, but I will provide detailed instructions for administering three such therapeutic baths below, and one of those should work well for you.

Administering a short-term dip to the affected seahorses that will provide them with some immediate (albeit temporary) relief. Dipping the seahorses will eliminate the bulk of the external parasites that are irritating them and causing the respiratory distress, providing them with quick relief, but they will eventually be reinfested once they are returned to the tank, so in the event you are dealing with an outbreak of parasites, Tamy, treating the main tank will eventually be necessary to resolve the problem once and for all.

Here are instructions for performing the therapeutic dips that may be helpful in this case, Tamy:

Methylene Blue Dip

First of all, you may want to consider administering a single, very brief (5-10 seconds — no more than 10 seconds maximum) dip in a solution of methylene blue between 30-50 ppm, as described below. Prepare the solution of methylene blue using saltwater from your seahorses tank ahead of time. Time the very short Methylene blue dip closely — maybe keep each seahorse in your hand while you dip it in the blue so there’s no fumbling around to capture it when time’s up — pull the pony out after 10 seconds and immediately return it to the main tank afterwards.

If you can obtain the Kordon brand of Methylene Blue (available at most well-stocked local fish stores), their suggested treatment protocol for treating external parasites as a dip is as follows:

For use as a dip for treatment of external parasitic protozoans:

(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.

See the following link for more information on treating with Kordon’s Methylene Blue:

Click here: KPD-28 Methylene Blue

If your methylene blue is not Kordon (KPD-28) Methylene Blue, then disregard the instructions above and follow the manufacturer’s instructions for using your brand as a bath or dip instead.

Another alternative would be to use formalin treatments at 1ml/gal for a 1 hour bath every other day until the scratching stops for up to 3 treatments, Tamy. However, bear in mind that formalin consumes oxygen and can therefore be hard on seahorses that are having breathing problems of any type. But formalin is very effective in eradicating gill flukes and protozoan parasites. The formalin does have the added virtue of working wonders with seahorses when they’re cloudy eyes are due to monogenetic trematodes or eye flukes. If you try the formalin baths, Tamy, be sure to observe the precautions outlined below:

Formalin Baths

Formalin (HCHO) is basically a 37% solution of formaldehyde and water. It is a potent external fungicide, external protozoacide, and antiparasitic, and is thus an effective medication for eradicating external parasites, treating fungal lesions, and reducing the swelling from such infections. It is a wonder drug for treating cases of Popeye caused by trematodes, and also eradicates external nematodes.

In my experience, provided it is administered properly, seahorses tolerate treatment with formalin very well at therapeutic dosages. For a long term bath the correct dose is 15 to 25 mg/L. [Note: 25 mg/L equals 1 ml (cc) of 37% formalin per 10 gallons of water.] This is done every other day for 3 treatments.

For a short term bath (dip) the correct dose is 250 mg/L. This would equal 1 ml (cc) of 37% formalin per 1 gallon of water. This should be for about 45 minutes to 1 hour. In my opinion, formalin is a safe, effective treatment for parasitic infections in seahorses providing you don’t exceed these dosages and observe the following precautions for administering the medication properly:

Many commercial formalin products are readily available to hobbyists, such as Kordon’s Formalin 3, Formalin-F sold by Natchez Animal Supply, and Paracide-F, sold by Argent Chemical Laboratories. Or whatever brand of formalin is available at your fish store should work fine, Pam.

A formalin bath simply involves immersing the seahorse in a container of saltwater which contains the proper dosage of formalin for a period of 30-60 minutes before transferring it to your hospital tank. Include a hitching post of some sort in the container and follow these instructions: place the fish in a three-gallon bucket or a similar clean, inert container containing precisely one gallon of siphoned, aerated tank water. Medicate the bucket of water with the appropriate amount of formalin for a concentrated bath according to the directions on the label. Place an airstone in the bucket and leave the fish in the bath for 30 minutes. If at any time the fish becomes listless, exhausted or loses its balance, immediately place the fish in clean, untreated water in your hospital tank.

I want you to be aware of these precautions when administering the formalin bath:
Formalin has limited shelf life and degrades to the highly toxic substance paraformaldehyde (identified as a white precipitate on the bottom of the solution); avoid using any formalin product which has such a precipitate at the bottom of the bottle.
Formalin basically consumes oxygen so vigorous aeration must be provided during treatment.
Time the bath closely and never exceed one hour of chemical exposure at this concentration.
Observe the seahorse closely during the bath at all times, and it show signs of distress before the allotted time has elapsed, remove it from the treatment immediately.

If you can obtain Formalin 3 from Kordon at your LFS, Tamy, these are the instructions you should follow for your formalin dip:

(a) To a clean, non-metallic container (i.e., a plastic bucket), add one or more gallons of fresh tap water treated with Kordon’s AmQuel . For marine fish use freshly prepared saltwater adjusted to the same specific gravity (or salinity) as in the original tank. Make sure the temperature in the container is identical to that in the aquarium
(b) Add 1 teaspoons of Formalin•3. This produces a concentration of 100 ppm. formaldehyde.
(c) Agitate the solution with an airstone and adjust for a moderately strong flow of air.
(d) Remove the fishes to be treated and deposit them in the container for a treatment period of not more than 50 minutes. Immediately after the treatment period, or if signs of distress are noted, remove the fishes to a previously prepared recovery tank. The fishes may be returned to their original tank, but the presence of the original disease-causing agents in the tank water may result in a reoccurrence of the disease condition.
(e) Observe recovering fishes. Make sure that tankmates do not molest them during recovery.
(f) Repeat treatment as needed, every week. Each treatment is very stressful to the treated fishes. Do not reuse the dip solution.

For additional information on treating fishes with Formalin 3 by Kordon, see the following web page:

Click here: KPD-54 Formalin-3

If you get another brand of formalin, just follow the instructions that it comes with for a concentrated bath or dip (not prolonged immersion or a long-term bath) or follow the following directions, courtesy of Ann at the org:

FORMALIN Short-Term BATH Dosage and Preparation Instructions
Active Ingredient: 37% Formaldehyde
Indication: external parasites
Brand Names: Formalin, Formalin-MS
1. Do NOT use Formalin that has a white residue at the bottom of the bottle. White residue
indicates the presence of Paraformaldehyde which is very toxic.
2. "Formalin 3" by Kordon contains only 3% Formaldehyde. Dosing instructions will need to be modified if using this product.
• Fill a small tank with aged, aerated, dechlorinated marine water. Match the pH, temperature, and salinity to that of the tank the Seahorse is currently in.
• Add an artifical hitch and 1-2 vigorously bubbling airlines. Formalin reduces dissolved O2 so heavy aeration is required.
• Add 1ml/cc of Formalin per one gallon (3.8 liters) of tank water. Allow several minutes for the Formalin to disperse.
• Place the Seahorse into the dip water for 45-60 minutes unless it is showing signs of an adverse reaction. If the Seahorse cannot tolerate the Formalin dip, immediately move it back to the hospital tank.
• Observe the Seahorse for 24hrs for signs of improvement.

Finally, here are the instructions for performing a freshwater dip, Tamy, which is a good option for many hobbyists who do not happen to have access to the methylene blue or formalin. Most seahorses tolerate the freshwater dips very well providing that the pH and temperature of the freshwater have been adjusted to match the temperature and pH of the seahorse tank. (Ordinary baking soda can be used to adjust the pH of the freshwater.)

Freshwater Dips

A freshwater dip is simply immersing your seahorse in pure, detoxified freshwater that’s been preadjusted to the same temp and pH as the water the seahorse is accustomed to, for a period of at least 10 minutes (Giwojna, Dec. 2003). It doesn’t harm them — seahorses typically tolerate freshwater dips exceptionally well and a 10-minute dip should be perfectly safe. Freshwater dips are effective because marine fish tolerate the immersion in freshwater far better than the external parasites they play host to; the change in osmotic pressure kills or incapacitates such microorganisms within 7-8 minutes (Giwojna, Dec. 2003). A minimum dip, if the fish seems to be doing fine, is therefore 8 minutes. Include some sort of hitching post in the dipping container and shoot for the full 10 minutes with your seahorses (Giwojna, Dec. 2003).

If you will be using tap water for the freshwater dip, be sure to dechlorinate it beforehand. This can be accomplished usually one of the commercial dechlorinators, which typically include sodium thiosulfate and perhaps a chloramine remover as well, or by aerating the tap water for at least 24 hours to dissipate the chlorine (Giwojna, Dec. 2003).

If you dechlorinate the dip water with a sodium thiosulfate product, be sure to use an airstone to aerate it for at least one hour before administering the dip. This is because the sodium thiosulfate depletes the water of oxygen and the dip water must therefore be oxygenated before its suitable for your seahorse(s). Regardless of how you detoxify the freshwater for the dip, it’s important to aerate the water in the dipping container well beforehand to increase the level of dissolved oxygen in the water. Many hobbyists leave the airstone in the dipping container throughout the procedure.

Adjusting the pH of the water in the dipping container so that it matches the pH of the water in the aquarium is a crucial step. Ordinary baking soda (sodium bicarbonate) will suffice for raising the pH of the water. If there is too much of a difference in the pH, there is a possibility the seahorse could go into shock during the dipping procedure. Preadjusting the pH will prevent that from happening. If you will are unsure about your ability to accurately adjust the pH in the dipping container, avoid this procedure altogether or be prepared to monitor the seahorse very carefully or shorten the duration of the tip to no more than about 2 minutes.

Observe the horse closely during the dip. You may see some immediate signs of distress or shock. Sometimes the horse will immediately lie on its side on the bottom. That’s a fairly common reaction — normal and to be expected, rather than a cause for concern, so don’t be alarmed if this happens. Just nudge or tap the seahorse gently with your finger if it lies down on its side. Normally, the seahorse will respond to the slight nudge by righting itself again and calm down for the duration of the dip. However, if it does not respond, stop the treatment.

Most seahorses tolerate the treatment well and experience no problems, but if you see continued signs of distress — twitching, thrashing around etc. — stop the treatment immediately and return the seahorse to normal strength saltwater. How well the seahorses tolerate a freshwater dip can vary from individual to individual and from species to species, but Hippocampus erectus seahorses tolerate the freshwater dips very nicely.

After you have completed the dip and returned the seahorses to the aquarium, save the dip water and examine it closely for any sign of parasites. The change in osmotic pressure from saltwater to freshwater will cause ectoparasites to lyse (i.e., swell and burst) or drop off their host after 7-10 minutes, and they will be left behind in the dipping water. Protozoan parasites are microscopic and won’t be visible to the naked eye, but some of the other ectoparasites can be clearly seen. For example, monogenetic trematodes will appear as opaque sesame seeds drifting in the water (Giwojna, Aug. 2003) and nematodes may be visible as tiny hairlike worms 1/16-3/16 of an inch long. Other parasites may appear as tiny dots in the water. Freshwater dips can thus often provide affected seahorses with some immediate relief by ridding them of these irritating pests and can also aid their breathing by flushing out gill parasites.

If you suspect a problem with parasites, the dip should be extended for the full 8-10 minutes if possible for best results.

Any of the dips are baths mentioned above should provide your seahorse with immediate relief and will serve as a helpful first aid measure to start with, Tamy. However, for a heavy infestation, it is also necessary to treat the seahorse tank in order to eradicate the parasites. There are a number of good antiparasitics that are safe to use in the main tank, and I would be happy to recommend a good antiparasitic for you to use if the therapeutic dip provides your seahorse with relief from its respiratory distress, indicating a potential problem with parasites.

Best of luck resolving your seahorse’s respiratory distress and lethargic behavior, Tamy.

Pete Giwojna, Ocean Rider Tech Support

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