Sad Seahorse?

Dear Mike:

Something is clearly stressing your male Brazilian seahorse (Hippocampus reidi) but I don’t have enough information to determine what the problem may be with so little to go on. It is unusual for a seahorse to remain in one spot without clinging to a holdfast, and darkening is another sign of stress in seahorses, as is a loss of appetite.

With no way to determine exactly what is stressing out your stallion, the best advice I can give you is to clean up the tank and perform a series of water changes to make sure that the water quality is optimum. A gradual decline in pH is a sign of deteriorating water quality, so that is where I would start, sir.

Aside from that, I would be happy to review the common aquarium stressors of seahorses with you in order to help you determine why your male is feeling out of sorts. As you know, Mike, seahorses that are subjected to chronic stress, which alters their blood chemistry, affects key hormones, and suppresses their immune system, become vulnerable to diseases and health problems just like any other fish. So the best thing you can do for your seahorses is to create a stress-free environment for them in which they feel right at home. We will discuss how to accomplish that and eliminate many of the common aquarium stressors later in this message, sir, but first let me review some of the obvious signs of stress or illness you should be aware of.

Respiratory distress is one such sign. Seahorses that are stressed or suffering from gill disease or parasites that attack the gills will exhibit rapid respiration, labored breathing, huffing, panting, yawning or coughing behavior, and other indications of respiratory distress. So familiarize yourself with your seahorse’s normal respiration rate, which will vary somewhat with water temperature and their activity level or degree of arousal/excitement, and subsequent changes in their normal breathing pattern can alert you to a possible problem.

Your seahorses’ respiration rate may increase naturally when they are feeding, actively courting, being handled, or excited in general, and then return to their normal resting respiratory rate afterwards. That’s natural and nothing to be concerned about. Symptoms of respiratory distress are ordinarily pretty obvious and you should have no trouble determining when your seahorse is laboring or struggling to breathe.

Seahorses that are stressed may also go off their feed, which is another obvious symptom that’s easy for the diligent aquarist to detect. So take a moment to enjoy the show when feeding your seahorses. Make sure they’re all eating well, and use this opportunity to look them over closely for wounds, injuries, or signs of disease. Seahorses are natural-born gluttons. Ordinarily, these galloping gourmets are ALWAYS hungry, so when one of these chow hounds is off its feed, that’s often an excellent early indicator that something’s wrong. Early detection of a potential problem can be the key to curing it, so it’s a good idea for the alert aquarist to observe his prize ponies while they put on the ol’ feed bag. Make sure they all show up for mess call, are acting normally, and have a well-rounded abdomen when they’re done eating.

Abnormal changes in coloration are another indicator of stress and certain disease problems. For example, seahorses will often darken over their entire bodies in response to stress, and pallor can be a sign of low dissolved oxygen levels or high CO2 levels since seahorses may blanch when subjected to hypoxic conditions. Skin infections and parasites that attack the skin will often cause a localized loss of pigmentation or discoloration, so be on the lookout for pale patches or white blotches that appear on your seahorse suddenly, particularly if these pale spots are not symmetrical (that is, they don’t appear in the same place on both sides of the seahorse’s body).

However, it’s important to distinguish between normal color changes and transitory color phases that all seahorses go through, and the type of abnormal changes in coloration we have been discussing above. Seahorses are truly the chameleons of the sea with a propensity for changing color in response to a wide range of environmental factors, hormonal influences, and behavioral interactions, or simply to better blend into their background.

With a little experience, you will become familiar with their normal color pattern and the transitory color phases they occasionally go through, which will make it easy to determine if an unnatural marking or suspicious pale blotches suddenly appears.

The hobbyist should also be aware that there are any number of environmental conditions that can affect the coloration of their seahorses, often by affecting the ability of chromatophores to contract and expand. These include the following factors:

Stress — seahorses often respond to stress by darkening.

Emotional state — when excited, seahorses typically brighten in coloration, reflecting a state of high arousal.

Competion for mates — dominant individuals brighten; subordinate seahorses darken in submission.

Poor water quality — high levels of nitrogenous wastes (e.g., ammonia, nitrite or nitrate) can cause chromatophores to contract and colors to fade.

O2/CO2 — low oxygen levels (or high CO2 levels) can cause colorful seahorses to fade and they will blanch when subjected to hypoxic conditions.

Background colors — seahorses will often change color in order to blend in with their immediate surroundings.

Medications — some antibiotics and malachite-green-based remedies negatively affect color.
Tankmates — seahorses may change their base coloration to blend in with the rest of the herd or to match their mate (or a potential partner).

Temperature — chromatophores tend to contract at high temperatures, causing colors to fade; cooler temps can make pigment cells expand, keeping colors bright.

Disease — skin infections (bacterial, fungal, or parasitic) can cause localized loss of pigmentation or discoloration of the affected areas.

Diet — seahorses cannot synthesize the pigments used in their chromatophores. It is therefore important to enrich their food with pigments such as carotenoids in a form that’s easy for them to absorb. If color additives are not provided, the chromatophores will gradually lose their pigments and the seahorse’s color can fade. Vibrance, for example, is exceptionally rich in Vitamins A and C as well as natural carotenoids, which are not found in Mysis relicta. This is important because the carotenoids are a class of yellow to red pigments, which include the carotenes and the xanthophylls. Like all cells, individual pigment cells have a limited life expectancy in the body and must be regularly renewed. Marine organisms cannot synthesize carotenoids, so if they do receive adequate amounts in their diet, they will have difficulty replenishing their red and yellow pigments. This means that the colors of bright yellow, orange, and red seahorses will gradually fade over time if their daily diet is lacking in carotenoids. So don’t neglect the enrichment step in your daily feeding regimen! If seahorses are fed a strict diet of Mysis relicta without additional enrichment, they may begin to develop dietary deficiencies over time, and both their health and coloration will eventually suffer.

Beware of tenderness and especially a loss of color or prehensility in your seahorse’s tail. Tail rot and white tail disease typically begin with a loss of prehensility in the very tip of the tail (Giwojna, Oct. 2003). At this stage, the seahorses can grasp large objects just fine, but cannot take hold of slender objects with a small diameter (Leslie Leddo, pers. com.). Next the loss of grasping ability spreads further up the tail and the seahorses begin to act as if their tails are very tender and sensitive. They will drape their tails over objects rather than grasping onto them and begin to drag their tails behind themselves, often arching the end of their tail upward in the shape of "U" (rather than the usual "J" or tight coil) as if to lift it off the ground and keep it from touching anything (Leddo, pers. com.).

Scratching and the erratic behavior are often an indication of the irritation ectoparasites cause. So when a seahorse attempts to scratch itself with its tail, or repeatedly attempts to scratch itself by rubbing against various objects, it’s often a sign of a parasitic infestation. If such symptoms persist, you’ll need to treat the seahorses with a good antiparasitic.

Buoyancy problems are another obvious sign of a health problem. Positive buoyancy — the tendency to float — can result from a number of causes such as hyperinflation of the swimbladder, pouch gas, or various forms of Gas Bubble Syndrome (GBS). Negative buoyancy — the tendency to sink — can be an indication of generalized weakness, and underinflated gas bladder, or fluid (ascites) building up within the abdomen or coelomic cavity.

Those are some of the signs of stress and early symptoms of health problems the diligent seahorse keeper should be aware of, Mike. One of the best ways to prevent bacterial infections, outbreaks of parasites, and other disease problems is to provide them with a stress-free environment. Many of the parasites and pathogens that plague our pampered ponies are ubiquitous — present in low numbers in most everyone’s systems or within the seahorse’s body itself (Indiviglio, 2002) as normal flora. As a rule, healthy fish resist such microorganisms easily, and they only become a problem when seahorse’s immune system has been impaired, leaving it susceptible to disease (Indiviglio, 2002). Chronic low-level stress is one of the primary factors that suppresses the immune system and weakens the immune response, opening the way to infection and disease (Indiviglio, 2002). Long-term exposure to stressful conditions is very debilitating. Among other effects, it results in the build up of lactic acid and lowers the pH of the blood, which can have dire consequences for seahorses for reasons we’ll discuss later.

When disease breaks out in an established aquarium it is therefore generally an indication that something is amiss with your aquarium conditions. A gradual decline in water quality is often a precursor of disease (Indiviglio, 2002). Poor water quality is stressful to seahorses. Prolonged stress weakens their immune system. And an impaired immune system leaves the seahorse vulnerable to bacterial, viral, and fungal infections to which healthy, unstressed seahorses are immune. As if that weren’t bad enough, there are a number of environmental diseases that are caused directly by water quality problems.

With this in mind, it’s important to review the most common stressors of captive seahorses. These include the design of the aquarium itself. A poorly designed seahorse setup that lacks adequate cover and shelter, or has too few hitching posts, will be stressful to the occupants (Topps, 1999). Seahorses are shy, secretive animals that rely on camouflage and the ability to conceal themselves for their safety and survival. A sparsely decorated tank that leaves them feeling vulnerable and exposed will be a source of constant stress (Topps, 1999). The seahorse setup should have plenty of secure hiding places so they can conceal themselves from view completely whenever they feel the need for privacy. It should be located in a low traffic area away from external sources of shock and vibration.

Needless to say, rapid fluctuations in temperature, pH, salinity and other aquarium parameters must also be avoided. A large aquarium of 40 gallons or more provides much greater stability in that regard than does a smaller setup. The greater the water volume in the aquarium and sump, the more stable the system will be.

Heat stress is especially debilitating and dangerous for seahorses due to a number of reasons (Olin Feuerbacher, pers. com.). For one thing, elevated temperatures can have a very detrimental effect on the immune system of fishes. This is because many of the enzymes and proteins involved in their immune response are extremely temperature sensitive (Olin Feuerbacher, pers. com.). Some of these protective enzymes can be denatured and inactivated by an increase of just a few degrees in water temperature (Olin Feuerbacher, pers. com.). So when seahorses are kept at temperatures above their comfort zone, their immune system is compromised and they are unable to fend off diseases they would normally shrug off.

At the same time heat stress is weakening the seahorse’s immune response, the elevated temperatures are increasing the growth rate of microbes and making disease organisms all the more deadly. Research indicates that temperature plays a major role in the regulation of virulence genes (Olin Feuerbacher, pers. com.). As the temperature increases, virulence genes are switched on, so microorganisms that are completely harmless at cooler temperatures suddenly become pathogenic once the water warms up past a certain point. Thus both the population and virulence of the pathogens are dramatically increased at higher temperatures (Olin Feuerbacher, pers. com.).

This is true of Columnaris and certain types of Vibrio. At cool temperatures these bacteria are relatively harmless, but at elevated temperatures they become highly contagious, virulent pathogens that kill quickly.

In short, it’s doubly important to keep seahorses at the proper temperature. Because of the reasons mentioned above and the fact that water holds less and less dissolved oxygen as it warms up, seahorses generally tolerate temps at the lower end of their preferred range much better than they handle temperatures at the upper limit of their range.

Incompatible tankmates are also stressful for seahorses. This includes not only aggressive, territorial fishes and potential predators but also inoffensive species that are restless, active fishes. Seahorses may be uneasy around fishes that are always on the go, swimming tirelessly back and forth.

Other common stressors for seahorses include overcrowding, overfeeding, stray voltage, and a host of issues related to water quality: ammonia or nitrite spikes, high nitrate levels, inadequate circulation and oxygenation, high CO2 levels and low 02 levels, low pH, etc., etc., etc (Giwojna, Jun. 2002).

In short, if hobbyists provide their seahorses with a stress-free environment, optimum water quality, and a nutritious diet, they will thrive and your aquarium will flourish with a minimum of problems. Preventing disease in the first place is infinitely preferable to trying to treat health problems after the fact.

When disease breaks out in an established aquarium it is therefore generally an indication that something is amiss with your aquarium conditions. A gradual decline in water quality is often a precursor of disease (Indiviglio, 2002). Poor water quality is stressful to seahorses. Prolonged stress weakens their immune system. And, as we have been discussing, an impaired immune system leaves the seahorse vulnerable to bacterial, parasitic, viral, and fungal infections which healthy, unstressed seahorses easily fend off.

At the first sign of a health problem:

Because diseases are so often directly related to water quality, or due to stress resulting from a decline in water quality, when trouble arises the first thing you should do is to break out your test kits and check your water chemistry. Very often that will provide a clue to the problem. Make sure the aquarium temperature is within the acceptable range and check for ammonia and/or nitrite spikes first. See if your nitrate levels have risen to harmful levels and look for a drop in pH.

Be sure to check your dissolved oxygen (O2) level too. A significant drop in O2 levels (6 – 7 ppm is optimal) is very stressful yet easily corrected by increasing surface agitation and circulation to promote better oxygenation and gas exchange. At the other extreme, oxygen supersaturation is a red flag indicating a potentially deadly problem with gas embolisms (Gas Bubble Syndrome).

If any of your water quality parameters are off significantly, that may well be the cause of the problem or at least the source of the stress that weakened your seahorses and made them susceptible to disease. And correcting your water chemistry may well nip the problem in the bud, particularly if it is environmental, without the need for any further treatment.

Clean Up & Perform a Water Change

After a quick check of the water chemistry to assess the situation, it’s time to change water and clean up. In most cases, the surest way to improve your water quality and correct the water chemistry is to combine a 25%-50% water change with a thorough aquarium clean up. Siphon around the base of your rockwork and decorations, vacuum the top 1/2 inch of the sand or gravel, rinse or replace your prefilter, and administer a general system cleaning. The idea is to remove any accumulated excess organic material in the sand/gravel bed, top of the filter, or tank that could degrade your water quality, serve as a breeding ground for bacteria or a reservoir for disease, or otherwise be stressing your seahorses. [Note: when cleaning the filter and vacuuming the substrate, your goal is to remove excess organic wastes WITHOUT disturbing the balance of the nitrifying bacteria. Do not dismantle the entire filter, overhaul your entire filter system in one fell swoop, or clean your primary filtration system too zealously or you may impair your biological filtration.]

At first glance your aquarium parameters may look great, but there are some water quality issues that are difficult to detect with standard tests, such as a decrease in dissolved 02, transitory ammonia/nitrite spikes following a heavy feeding, pH drift, or the gradual accumulation of detritus. A water change and cleanup is a simple preventative measure that can help defuse those kinds of hidden factors before they become a problem and stress out your seahorses. These simple measures may restore your water quality and correct the source of the stress before your seahorse becomes seriously ill and requires treatment.

Okay, Mike, for whatever it’s worth, those are my thoughts on the matter. I would suggest starting out with a general clean up and a series of water changes to make sure that your water quality and dissolved oxygen levels are where you want them to be.

Be sure to double check your water temperature as well, Mike. The aquarium temperature can gradually creep up to uncomfortable levels during summertime heat waves and heat stress is very debilitating to seahorses.

Best of luck restoring your prolific pony to good health again, sir. Here’s hoping that he is soon back to courting his mate again and producing another brood of young for you.

Respectfully,
Pete Giwojna

Dear Mike:

You’re very welcome.

It sounds like you’re on top of the situation and that you’ve already taken the appropriate commonsense precautions at this point. I would mix up additional saltwater and preadjust it to the same temperature, pH, and specific gravity as your seahorse tank so that you’re ready to perform additional water changes or to set up a hospital tank, if necessary.

You can send photos or a video clip to me off list at the following e-mail address, Mike: [email protected]

I would be happy to look them over to see if anything more suggests itself, sir, but I probably won’t be able to determine anything new that you have not already noticed as a first-hand observer.

It would also be helpful if you can provide me with some background information regarding your seahorse tank, Mike. Just let me know how big the aquarium is, what kind of equipment you’re using, and provide me a list of the aquarium inhabitants (including the cleanup crew), along with your current aquarium parameters (water temperature, specific gravity, pH, ammonia, nitrite, nitrate).

Respectfully,
Pete Giwojna