Yes, sir, seahorses are like other tropical marine fish. They are susceptible to the usual diseases and infections and parasites that plague other reef fish, as well as a few afflictions that are specific to seahorses (e.g., prolapsed pouch, white tail disease, and gas bubble syndrome). The bony exoskeleton and protective slime coat of Hippocampus gives the seahorse limited immunity from certain ectoparasites such as marine ich (Cryptocaryon irritans) and marine velvet (Amyloodinium), so the telltale white spots that characterize those conditions may never show up (or may be visible only on the unarmored fins). So those particular diseases are relatively uncommon in seahorses, although when they do occur, the parasites can still freely invade the seahorse’s gills, with deadly results.
But your Ocean Rider seahorses come to you direct from a High-Health aquaculture facility and are certified to be free of pathogens and parasites when they arrive, so if you can provide them with a stress-free environment and proper care, you should find them to be quite hardy and relatively disease resistant.
Even so, 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, Billy, 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. For example, Billy, your Mustangs have a preponderance of melanophores and tend to be dark (earth tones) or cryptically colored most of the time. But ‘stangs also have bright pigment cells and they can brighten up when the occasion calls for it, such as during courtship or when competing for mates.
I own a pair of these spirited steeds myself, and have watched them go through a number of color phases from month to month. One has settled on gray-green as its base coloration for the moment, and the other ranges between rust, burnt umber, and orange, but always with contrasting beige bands. Last season, the male adopted a rich ochre yellow as his everyday attire (still with the same beige bands, though), while the female displayed a dark purplish ensemble with definite greenish highlights. When courting, they consistently brighten to a pearly white and a creamy yellow respectively. They make a handsome couple, and I find my Mustangs to be very attractive specimens in all their guises.
You can expect your Mustangs to exhibit various color changes from time to time as well, Billy. That’s perfectly normal and to be expected. 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 prehensility 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.
Those are some of the signs of stress and early symptoms of health problems the diligent seahorse keeper should be aware of, Billy. One of the best ways to prevent bacterial infections 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 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. Good seahorse husbandry and diligent maintenance will be rewarded; sooner or later, negligence and poor aquarium management will be punished.
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.
Aside from keeping your seahorses stress-free, Billy, one other thing you can do to help prevent certain disease problems is to install an ultraviolet sterilizer on your seahorse tank, as discussed below:
Although it does not improve water quality to nearly the same degree as an ozonizer used in conjunction with a protein skimmer, UV radiation in the proper range (295-400 nanometers) is known to help oxidize phosphates, metabolites, organic molecules and nitrogenous compounds through the incidental production of ozone (Fenner, 2003a).
The primary benefits UV sterilization provides, however, are disease reduction and the reduction of nuisance algae. Ultraviolet radiation can be very effective in reducing free-floating algae, bacteria and microbes in general, certain parasites while in the free-swimming stages of development, and other suspended microscopic organisms (Fenner, 2003a). Seahorses are prone to a number of serious bacterial problems such as Vibriosis, and a properly installed and maintained UV sterilizer can be invaluable in reducing the incidence and spread of such infections. When properly used, UV sterilization can reduce microbial levels in the aquarium to the low levels normally found in the wild or below (Fenner, 2003a).
For best results, the UV sterilizer must be properly sized, operated, and maintained. In order to provide a good kill rate per pass, the effective dwell time (the length of time the water is exposed to UV radiation while passing through the sterilizer) should be maintained at or above roughly twenty gallons per hour flow per watt of UV (Fenner, 2003a). This sounds complicated, but selecting the right sterilizer for your needs is actually very easy. Every manufacturer provides guidelines to help the hobbyist choose a unit and a pump that provide the proper wattage, flow rate and exposure time for any given application.
To assure efficient transmission of the proper wavelengths, sleeves (i.e., the quartz jacket that shields the lamp) must be kept clean and UV bulbs must be replaced at regular intervals. Equally important, the aquarium water should be filtered before it passes through the sterilizer. For maximum efficiency, make the UV sterilizer the final component of an in-line filtration system, so that the water has already passed through your mechanical, biological and chemical filtration media before it flows through the sterilizer (Fenner, 2003a). Do not operate your UV sterilizer during the break-in period when a new aquarium is being cycled and the biological filtration is becoming established. It is counterproductive to reduce microbe levels and nutrient levels when the aquarium is cycling.
Ultraviolet sterilizers are not necessary for maintaining seahorses, but nowadays I would not attempt to keep wild-caught seahorses without one. Hardy, disease-resistant farmed-raised seahorses can do just fine without them, and reefers often frown on UV because it reduces the population of microscopic planktonic organisms filter-feeding invertebrates require. But in my opinion a UV sterilizer makes a very useful addition to the filtration system of the average seahorse setup. The fish farms and aquaculture facilities that raise captive-bred seahorses employ UV radiation in their nurseries and grow-out tanks, and there is no reason the home hobbyist should not take advantage of this technology as well.
Finally, Billy, there is an excellent new book about the diseases of seahorses that you would find very informative. Dr. Martin Belli, Marc Lamont, Keith Gentry, and Clare Driscoll have done a terrific job putting together "Working Notes: A Guide to the Diseases of Seahorses." Hobbyists will find the detailed information it contains on seahorse anatomy, the latest disease diagnosis and treatment protocols, and quarantine procedures to be extremely useful and helpful. It has some excellent dissection and necropsy photos as well as a number of photos of seahorses with various health problems. This is one book every seahorse keeper should have in his or her fish-room medicine cabinet, and I highly recommend it! In time of need, it can be a real life saver for your seahorses. It’s available online at the following web site:
Click here: Working notes: a guide to seahorse diseases > books > The Shoppe at Seahorse.org | CafePress
Best of luck with your new seahorses, Billy! If you feed them properly, provide them with a nutritious diet, and maintain good water quality, they should remain healthy and disease free for years to come.