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The Most Common Fish Diseases You Should Know

The Most Common Fish Diseases You Should Know

If you own a fish, you may notice at times that it looks different or that it’s showing strange behavior. If that’s the case, your fish might have a disease. The first step to treating the disease properly is to know what it is. Here are some of the most common fish diseases you should know.

Swim Bladder Disease

Swim bladder disease is most common in betta fish, goldfish, and bony fish. This disease is also known as floating disorder because fish with the disease have a tendency to imitate dead fish.

Signs of Swim Bladder Disease

Some fish with swim bladder disease swim upside down and float to the bottom of the tank. They may also float upside down at the top of the tank, or they may swim sideways. Fish don’t have the ability to swim upright in a straight line, so they may struggle to rise to the surface for food. Since fish with this disease suffer from bladders that don’t work properly, they might also lose their appetite.

Causes of Swim Bladder Disease

Many factors may cause swim bladder disease, the most common being bladder compression. Eating too quickly or too slowly; the enlargement of nearby organs; or low water temperature may cause this disease.

Another possible cause of swim bladder disease includes physical trauma to the fish’s body. A fall, an object hitting the tank, fights with other fish, or low water temperature can cause physical trauma. Although low water temperature may seem like a strange cause of swim bladder disease, it causes stress, which affects the fish’s body.

Treatment for Swim Bladder Disease

To treat swim bladder disease, you must watch your fish for any unusual or absent bowel movements. To notice an unusual bowel movement pattern, do not feed your fish for two to three days.

Also, purify your water. The purification process involves adding one to two teaspoons of non-iodized salt to the tank. You should also include the number of Epson salts equivalent to the number of gallons of water in the tank. After taking these steps, make sure the pH and nitrate levels are correct.

After the purification process, check your water temperature. If it’s too cold, slowly increase the temperature to 68 degrees. Correcting the water temperature may take several days.

Finally, change your fish’s diet. Only feed it peas and live food for a week. Then, slowly increase food quantities.


Another common fish disease is dropsy, which got its name from the fish’s belly dropping down. Dropsy can affect all types of fish, but it mostly affects fish with weakened immune systems.

Cause of Dropsy

The biggest cause of dropsy is a tank infected with a dropsy-causing bacteria. The bacteria weakens the immune systems of fish that are already unhealthy and stressed out. Poor water quality, poor nutrition, or other aggressive fish can cause stress.

Signs of Dropsy

Some signs of dropsy include a swollen body, pale gills, scales that look like pinecones, and clammed fins. Fish may also show low appetite and fatigue. Internal organs such as the liver and the kidneys may also become damaged.

Treatment for Dropsy

For tanks with multiple fish, transfer all sick fish to a hospital tank. Make sure the water temperature in the hospital tank is close to the temperature of the original tank. For every 10 gallons of water in the hospital tank, add 2.5 teaspoons of Epsom salts.

After you have purified the water, feed your fish antibacterial fish food for seven to 10 days. Hopefully, your fish will improve within that time range. If the fish do not improve, add Maracyn Two to the aquarium. This medication easily absorbs through the fish’s skin and fights against bacteria.


ICH is a disease also known as white spot disease due to the white spots that develop as the main symptom. ICH is a very contagious disease, so if you have multiple fish, it’s important to treat the sick fish as soon as possible.

Causes of ICH

Parasites called ICH protozoan, which attack fish and create crystal-like spots on their bodies, commonly cause ich. The parasites attach themselves to fish so that they can feed on them. Eventually, they fall off and multiply themselves. After the parasites finish multiplying, a cyst in the ground opens and releases hundreds of new ICH protozoa. A few days after the new parasites start swimming, they attach themselves to new fish and feed on them. The cycle repeats itself.

Signs of ICH

The main sign of ICH is white spots on the body of your fish. This physical sign makes the disease easy to recognize. Some other signs include isolation, fast breathing, fatigue, rubbing against surfaces, and loss of appetite.

Treatment for ICH

To treat ICH, you must first identify whether it was caused by parasites or a weakened immune system from previous stress. The difference between the two is that with parasites, you might notice an increase of spots on many parts of the fish’s body within a day. Stress ICH, on the other hand, doesn’t cause a rapid increase in spots, and it usually only affects one part of the body. If many fish are in the aquarium, you must quarantine the sick fish.

After you separate the healthy fish from the sick fish, you should give the sick fish a medication called Aquarium Solutions ICH-X. This medication is safe and effective for all types of fish. If you have sensitive fish, use 5 ml of full-strength medication for every 10 gallons of aquarium water.

After the first day of treatment, change one-third of the aquarium water. Give the fish the same dose you would give them for the entire aquarium volume. Continue this treatment every day until the first day after the signs disappear. This will help you ensure there are no more cysts.

To prevent ICH from returning, change the water regularly and make sure the temperature is 78 to 80 degrees Fahrenheit. Also, remove the fish. If the parasites don’t have a host for two full days and are kept in 80-degree water, they will die.

Now that you have enough information about the most common fish diseases you should know, you can keep your fish happy and healthy. Here at eFish Mox, we sell many types of fish antibiotics, some of which include fish clindamycin, penicillin, and amoxicillin.

The Most Common Fish Diseases You Should Know

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