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A Quick Disease Guide for Common Captive Seahorse Maladies By Christopher Burns |
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This living essay is intended to help the hobbyist identify and treat an infection in their fish. It, by no means, is complete, nor definitive, and thus the author bears absolutely no responsibility for its usage. Use this guide to assist you in troubleshooting pathogenic problems, but, as always, your own common sense and knowledge should prevail. If in doubt, question it! | |||
| Pathogen Name/Taxonomy | Photo Click to view larger picture |
Causes/Characteristics/Virulence | Treatment |
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Pouch Emphysema (Air in the Pouch, Pouch Bloat) |
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Pouch emphysema can be traced to decaying embryonic matter in the pouch, producing gasses and causing the pouch to bloat, and/or physical air bubbles in the water column entering the pouch during mating/courtship rituals and/or routine exercise and maintenance of the pouch environment. This is not to say that this is either empirically determined or the sole cause, but I believe there is such an abundance of anecdotal evidence, coupled with the ease of inciting this condition in consistently reproducible fashion, that it makes a very strong correlation indeed. Another possible cause is some sort of bacterial infection in the pouch. In chronic, recurring cases where the mating ritual has not taken place and there are not physical bubbles present in the water column, this is most likely cause.
This condition manifests as a bloating or swelling of the pouch in the male, which in turn, prevents normal locomotion. The horse will float to the surface and become stuck there, unless he is a very strong swimmer, in which case he may be able to overcome the bouyancy problem for a while. The major problem with this condition is the weakening of the fish during the symptomatic phase. As the horse struggles to overcome the bouyancy problem, he will become weaker and weaker, potentially to the point of not being able to eat, and thus may starve to death. Another problem is that the fish may get caught in bad areas such as filtration intakes/returns or against heaters, without being able to free himself. |
Treatment of this malady is to first determine the cause of the problem. Check for air bubbles in the water column from malfunctioning powerheads or powerheads too close to the surface, protein skimmer returns, or other sources, and rectify them. If there are no air bubbles present in the water, then check the overall tank size, especially the height, with respect to the ailing seahorse. A typical rule of thumb for tank height is 3 times the horse's height. So, if you have an 8" tall seahorse, the tank he lives in should be 24" deep or more. This will allow ample space for the fish to properly locomote and flush his pouch as necessary.
For immediate relief, evacuate the pouch of the built-up gas. Details on evacuating the pouch can be found in the article Quick and Easy Pouch Evacuation. For chronic, recurring pouch emphysema, an antibiotic flush is recommended. Mix a dilute solution of Neomycin, Kanamycin, or Erythromycin, by taking 1/10 of a teaspoon and mixing with 20cc of tank water. Using small pipette, introduce approximately 0.2cc - 0.4cc of the solution (depending on the size of the horse) into the pouch through the pouch oriface. DO NOT PUNCTURE THE POUCH WITH A HYPODERMIC NEEDLE, or irritate the pouch oriface by being too forceful. Allow the solution to remain in the pouch for 2-4 hours, and then flush again with clean tank water. Repeat this process for 3 days. |
| Internal Gas Bubble Disease |
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First off, let me say that in my opinion, this is a very different malady than Pouch Emphysema. Pouch Emphysema has distinct, reproducible etiology, whereas this condition has unknown etiology and is difficult to reproduce.
The cause of this malady is the source of great debate. It is thought to be brought on by either gas supersaturation or bacterial infection. Unfortunately, once this malady takes hold, the tissue damage is usually too severe for the fish to recover. Symptoms include bouyancy problems initially, but progresses to subcutaneous bubbles, exophthalmos, and then finally, the grotesque bloating seen here. Sadly, this malady is usually fatal by the time it is detected, diagnosed, and treated. However, recent reports have show some promising results with two treatments, so there may, in fact, be hope. |
Decompression - By submerging the horse in a deeper-than-the-tank column of water for an extended period of time. The depth should be something like 3 times the tank height, and the horse must be kept at the bottom of the water column for many hours. This treatment may relieve the symptoms, but if the fish has been in this condition for too long, and internal damage has occurred, recovery is unlikely.
Acetazolamide injection - Acetazolamide has been found to have positive effect on this condition, however the medication is difficult for hobbyists to get, and must be administered intra-muscularly, which an be a tricky injection for a novice, especially with a seahorse. |
| External Gas Bubble Disease |
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These air bubbles manifest just beneath the skin (subcutaneously), and are often the first signs of a far more grave problem. The bubbles interfere with bouyancy and locomotion, stressing the fish, weakening it, and can eventually kill it in severe cases. Gasses trapped beneath the skin are believed to be caused by either bacterial infection (not the opinion of the author), by air bubbles in the water column, or by gas superstauration in the water column. The author has experienced cases where the environment of healthy horses was equipped with a poorly functioning skimmer that created copious amounts of pin-head-sized bubbles, and within days, several fish had demonstrated subcutaneous gas bubbles. It was observed that the only fish with this symptom were those that hitched directly in the path of the bubbles.
In the case of gas supersaturation, these subcutaneous bubbles will often appear in areas of thin skin, i.e. around the eyes, along the tail, etc. In this case, the gasses dissolved in the water column are escaping into the tissues of the fish, much like with nitrogen narcosis experienced by scuba-divers who descend too far and do not take the proper time to ascend. |
As the bubbles get larger, they will impede the horse's ability to locomote. Therefore, you must lance the bubbles with a sterile, thin needle, in order to relieve the fish. Do this by puncturing the bubbles beneath the skin PARALLEL to the body of the fish. DO NOT POKE INTO OR TOWARDS THE BODY OF THE FISH. Gently compress the lanced bubble to evacuate the gas, and then apply an antiseptic. Do not perform this procedure on bubbles near the eyes as you can easily damage the eyeball itself. |
| Exophthalmos / Pop-Eye |
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Pop-Eye can be brought on by diverse factors such as gas supersaturation and internal fungal infection (usually by Ichthyosporidium hoferi), parasitic infestation (usually by trematodes), or bacterial infection (usually by Mycobacterium marinum). In all cases, the eyeball itself protrudes grotesquely from the socket, which can be damaging to the organ itself or the surrounding tissue if left unchecked. Although exophthalmos is not, itself, lethal, the causative agents can easily be if not treated promptly and accurately. |
Treatment should be applied in the following order, unless you can identify the causative agent with confidence and certainty.
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"Flesh Eating Bacteria" Cryptobia sp. / Costia sp. |
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Both Costia sp. and Cryptobia sp. can be fatal. They attack the largest organ of the host, the skin, and do grotesque damage, literally eroding the flesh. In their wake are open sores, similar to Vibrio sp. infections, which are, fortuately, not common in seahorses. Initial symptoms include cloudiness (turbidity) of the skin, sloughing of the skin, cloudy eyes, localized swelling, and lesions. As the malady progresses, lesions will appear, and will become bloody, eventually eroding all the way down to the bone. If caught early, both maladies are easily curable with the appropriate medication. | Topical solutions have yielded some promising results, however, care must be taken to not allow the mixture to get into the fish's mouth, eyes, or gills, making this a difficult treatment. Another promising treatment is a topical solution of high-dose Sodium Chloride, which is safer if ingested. Sodium chloride treatment is not recommended if the lesions are bloody. |
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Snout Rot Saprolegnia sp.? |
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Snout Rot is commonly attributable to either severe bacterial infection (usually Costia sp.) or to external fungal infection of Saprolengia sp.. Initial symptoms include discoloration and slight swelling in the area, refusal to eat, and lethargy. As the disease progresses, the tip of the snout will inflame and erode, inhibiting the fish's ability to feed. This is a difficult malady to cure, and often progresses to the point where the snout is damaged so badly that feeding is no longer possible.
Differentiation between the fungal form and the bacterial is by magnified examination. In cases of fungal etiology, the snout will have a pinkish hue, and slightly elevated convoluted growths similar to cauliflower in appearance. Bacterial cases will display flaking or sloughing skin as the tissue erodes, and are typically white in color. |
Topical solutions have yielded some promising results, however, care must be taken to not allow the mixture to get into the fish's mouth, making this a difficult treatment. Another promising treatment is a topical solution of high-dose Sodium Chloride, which is safer if ingested. Antifungal medications such as Nifurpirinol or Phenoxyethanol are also very effective but unless ingested by the fish, must be used in the tank and can be damaging to other inhabitants. |
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External Parasites Cryptocarion irritans, Amyloodinium ocellatum, Monogenetic Trematodes, Isopods, etc. |
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Macro-parasites such as flukes and isopods can be seen with careful examination. However, often they will take on the coloration of the host, so you may be looking for odd bumps on the fish, rather than the telltale signs of the organism itself. Micro-parasites such as Cryptocarion irritans and Amyloodinium ocellatum rarely attack seahorses, assumedly due to their tough, but thin, skin not providing enough depth for the parasite to insert and incubate. Other micro-parasites such as monogenetic trematodes are far more common in seahorses.
Symptoms include cloudy eyes, erratic swimming, flashing (scraping on the rocks, decorations, or substrate), rapid breathing, weight loss, and listlessness. Parasites, once given the chance to get a foothold can cause a terrible death for your fish as they sap the energy and vitality from their host like little vampires. When treated with the proper medications, this pathogen can be completely eradicated and the fish can experience a complete recovery. |
Macro-parasites should be removed carefully so as not to damage the fish. Wound sites from adhesion of the parasite should be treated with a topical antibacterial agent to prevent secondary infection.
Micro-parasites such as Cryptocarion irritans or Amyloodinium ocellatum should be treated first with a freshwater dip. If the problem persists, you may try pepper-based products such as RxP or Stop Parasites!, however, these products have limited reported efficacy, and are scrutinized heavily by many in the hobby. The next level of treatment includes the staining or tanning agents, such as GreenEx, Acriflavin, Revive (Rally) and Methylene Blue. Care must be taken when using these as some inverts are sensitive to GreenEx and Acriflavin, and Methylene Blue will decimate nitrifying bacteria. Finally a Formalin bath can be used to eliminate the pathogen. Monogenetic trematodes should be first treated with a freshwater dip, then Formalin as a dip, and finally the best, but most dangerous solution, Trichlorfon. Trichlorfon is highly toxic to marine fish and deadly to invertebrates. It is also difficult to obtain, so you may need to see your vet or local public aquarium in order to find it. |
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Internal Parasites Digenetic Trematodes, Cestodes, Nematodes |
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Internal parasites are typically organisms such as trematodes (commonly called "flukes"), cestodes (commonly called "tapeworms"), or nematodes (commonly called "roundworms"). These organisms usually attach at some point along the digestive tract or liver of the host animal by use of a sucker or a rostrum (hook-like proboscis), feeding off the incoming nutrients, blood, and tissue. This prevents the host from obtaining appreciable nutrition for its meals, resulting in a gradual wasting, and oftentimes in complete refusal to eat, assumedly due to discomfort. Left unchecked, these parasites will literally consume the host animal, leeching vital nutrients right out from under it, causing tissue damage, hemorrahging, and eventually death. |
In order to be effective, the following treatments must be ingested by the patient.
Metronidazole is a good first choice medication as it is very safe to use, not effecting the bio-filter or invertebrates, and almost impossible to overdose with sensible usage. Niclosamide is a very effective medication versus nematodes and cestodes, but it can be difficult to obtain. You may need to check with a vet or local public aquarium to find it. Praziquantel is a very effective medication versus digenetic trematodes, but it can be difficult to obtain. You may need to check with a vet or local public aquarium to find it. |
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