Tropical Fish Diseases

Keeping aquarium fish is a fun hobby that many people share, however, from time to time, fish do get sick. Why is the color changing? Why is my fish acting this way? There are many tropical fish diseases with many different symptoms and treatments. Here you will find a list of symptoms you can compare your freshwater fish with, giving you some insight into what the diseases might be, if at all, and how you can treat the ailment. If you cannot find the symptoms of your freshwater fish and are looking for an answer, please visit your local fish expert at any local aquarium shop or pet store.

Cotton-Wool Disease

Visible Symptoms: Off-white spots or marks around the fins, body and mouth of the fish, white cotton like fungus like puffs around the mouth region, red ulcers on the fishes body, frayed fins, "shimmy" instead of swim constantly, thin appearance, and lack of hunger.

Causes: Improper aquarium care including changing the water, over stocking of fish in one fish tank, poor water quality and sudden changes in the condition of the water can cause healthy fish to get this disease.

Treatment: In early development of this disease, mainly the outside of the fish is affected. This can be treated by using a phenoxyethanol-based or an antibacterial medicine. If the disease has entered the fish and affected their organs, then antibiotics are necessary. Visit your pet store to purchase necessary antibiotics.

Dropsy or Malawi Bloat

Visible Symptoms: Protruding scales, larger, swollen belly, base of fins become red, ulcers visible on fish's body, long and pale fecal casts, lack of hunger, darkening in color, pale colored gills and bulging eyes. In some instances, fluid builds up in the fish's body causing discoloration of internal organs.

Causes: Malawi Bloat is caused by the fish eating too much protein and not enough vegetable based foods. Also, being an internal disease, a poorly maintained aquarium including poor water quality may cause this disease. Dropsy is also brought on my poor aquarium conditions, and may occur in fish that have other illnesses.

Treatment: It is best to remove fish suffering from this disease to a separate tank and ensure they are getting proper food in proper proportions and good, clean water conditions. This the health of the fish does not improve, visit your aquarium fish pet store and inquire about a broad-spectrum antibiotic.

Fin Rot

Visible Symptoms: Frayed, split and obvious deterioration of the fins.

Causes: This disease usually occurs when a fish has some other illness. Fighting, rough handling, overcrowding, improper water conditions and poor feeding are all causes of Fin Rot. In cold water fish with long tails, Fin Rot may occur when the water temperature drops below 10C/50°F.

Treatment: Proper aquarium care such as water quality and temperature can help prevent this disease from ever occurring. Adding aquarium salt may help prevent this disease in some freshwater fish. Antibacterial medication will usually cure most outbreaks. In persistent cases, antibiotics may be used. Seek these medicines from your tropical fish pet store.

Fish Lice or Fish Louse

Visible Symptoms: Fish lice, or fish louse, are flat-bodied crustaceans that can measure up to 10 mm in diameter. They will swim up to a fish, mostly slower moving fish, and attach itself to the fish's body by two suckers. They feed on the blood of the fish by biting into the fish with its sharp mouth parts. This irritation causes fish to jump out of the water, or rub themselves against rocks, and red cuts may develop where the parasite is feeding. These small cuts may become seriously infected with bacteria or fungus.

Causes: Fish lice are mainly found on newly imported/purchased fish, and are mostly problematic in outdoor ponds during the summer when the temperature is warmer. Because the parasitic fish lice bite and suck the blood of their fish host, they may transmit infections from fish to fish. Fish lice are mostly dangerous in smaller fish.

Treatment: Insecticides may treat most adult and juvenile crustacean parasites. One or two treatments should suffice, but consult a local fish expert at your nearest pet store for precise instructions. Some species may be sensitive to these medications, so it is important to remove these diseased fish and place them in a separate tank for the duration of the treatment. Treat separated sensitive fish with a 30 minute bath of potassium permanganate before reintroducing them into the aquarium.


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