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Veterinarians Near Ashburn, Virginia, 20146

Animal Medical Centers of Loudoun: Ashburn Farm

Animal Medical Centers of Loudoun: Ashburn Farm

43330 Junction Plaza Blvd #172, Ashburn, VA 22066

VCA Herndon-Reston Animal Hospital

VCA Herndon-Reston Animal Hospital

500 Elden Street, Herndon, VA 20147

Animal Medical Centers of Loudoun: Brambleton

Animal Medical Centers of Loudoun: Brambleton

42385 Ryan Rd #112, Ashburn, VA 20147


common fish diseases to know about

Fish; they make great pets. Easy to care for, low maintenance to keep, it’s no surprise that we own more than 142 million freshwater fish in America, making them one of the most popular pets.

However, much like any living being, they are prone to disease and ill-health in certain conditions.


The lifespan of a fish can vary. A common carp for instance can live up to 20 years, while a mahi-mahi will be lucky to see seven years. But goldfish and many other home-cared for fish can last anywhere from five to ten years in the right conditions.

Health Problems

Some of the more common health aliments that fish may suffer from include:

Ammonia poisoning: When high levels build up you can start to see red or purple gills, and fish gasping at the top of the water for air. These can however be reduced by a neutralizer accompanied by a partial water change. Frequent checking of levels can help prevent build up.

Columnaris: This is a bacterial infection that materializes as lesions on your fish. These are very common and can look like mold. This is often the result of poor water quality and diet, and can therefore be easily addressed.

Dropsy: Signs to look out for include a bloated belly, raised scales and a supposed pine-cone appearance. Dropsy is a disease that can be caused by bacteria and viruses, and is easily mistaken as a pregnant fish. Dropsy causes a swollen or hollow abdomen, hence the common misconception that the fish is pregnant. Fish suffering from dropsy will lose their appetites and become listless, and once damage from the disease reaches the kidney, it basically becomes incurable. It is thought that infected food and bad water can lead to dropsy outbreaks in aquariums. Unfortunately, even when dropsy is discovered early, it can be very difficult to cure. There are commercially available remedies that can help with the treatment of dropsy.

Fin rot: Another bacterial infection that is typically seen in frayed and white fin edges. Fin rot, as the name suggests, affects fish fins. It can cause them to turn opaque and possibly even become blood streaked. The fin can continue to erode until the rot reaches the base of the fin, at which point the fish will die. Fin rot is caused by bacteria and is not something that normally affects healthy fish. Those that are stressed or have already damaged fins are far more susceptible to fin rot. Fish can be treated with a course of antibiotics and a complete clean-out of the tank.

Fungal infections: These are very common in fish since fungus spores are common within an aquarium. Fish that have already damaged skin or gills are more susceptible to fungal infections.  It often starts as a white growth that looks a little like cotton. This can be treated with anti-fungal medications that also fight bacteria in the environment to keep it under control.

Ich: Ick, or White Spot Disease, is a very common and very contagious disease that affects fish. Ick causes fish to develop little, grain-like spots all over their body. In addition to acquiring spots, a fish may also try to rub itself against hard surfaces in the aquarium, almost making it appear as if the fish is trying to scratch an itch. Ick is a parasitic disease where the parasite spends part of its life on the skin of the fish, where cysts develop. These cysts can then fall off the fish, releasing thousands of new parasites that can prey on other fish in the aquarium. If not noticed in the early stages, Ick can be very difficult to control. Adding salt to aquarium water can help but care must be taken as different species of fish tolerate salt levels differently. There are also medications available for treating infected fish.

Nitrate poisoning: Fish with brown or dark gills, along with gasping for air at the water surface are usually indicators of this problem. Good news is that treatment is available in the form of a neutralizer accompanied by a partial water change. Nitrate can be lethal to fish in high levels, so it’s important to check your tank regularly.

Velvet: A parasite called Oödinium is to blame for this disease. Named for the velvety layer it forms on the skin, it can often appear in golden, bronze or rust color. In advanced cases, it can also result in weight loss and inconsistent breathing. It can be treated with copper sulfate as a course of treatment.

Swim Bladder Disease: A fish’s swim bladder is what helps them to remain buoyant. When there is an issue with the swim bladder, a fish will lose its buoyancy, and this is one of the first indications that it may be suffering from swim bladder disease. Swim bladder disease can develop when the membrane of the swim bladder has been damaged. There is a lot of debate as to what causes swim bladder disease in addition to debate over how to treat it.

Anchor Worms: Anchor worms are parasites that attach themselves to infected fish. They are also able to burrow into the fish’s skin and enter the muscles. Once this happens, the worms develop and release eggs prior to dying. This causes damage to the fish that can lead to infection. Fish that are suffering with anchor worms often look like they have little whitish colored threads protruding from their bodies. One treatment option is to physically remove the parasites from the fish and clean the wounds with antiseptic solution. The other common treatment is bathing the affected fish in saltwater for approximately five minutes for a few days in a row until the parasite falls off.

What to do if my fish is unwell?

If your fish is feeling blue, don’t worry. Modern medicine has a number of helpful treatments to restore them to their previous health.

First of all, if you notice that your fish is unwell, try isolating them, preferably in another tank. Should they have a contagious disease, this will minimize their chance of passing it on.

Use the opportunity to check the tank’s water quality and pH levels.

Sick fish may have open sores, or swollen features, they may have lesions or discoloration, be off their food, or may lay at the bottom of the tank.

Once you have identified the symptoms, head down to your pet shop to see if they have suitable medicine for your fish. They make also recommend treatments for the tank, and/or other fish too.

Stay healthy

Here’s some tips for keeping your freshwater fish healthy:

  • When introducing new fish, do so in a separate tank at least 5-10 days before adding to the main tank, so you can check their health.
  • Maintain pH levels.
  • Don’t overcrowd the tank, as this can lead to lower levels of oxygen in the water.
  • Make sure the water is balanced to support their life and replace 25 per cent at least once a month.
  • Do not overfeed your fish.
  • Ensure you keep it the tank at the right temperature. This means keeping it in the right environment too.
  • Regularly check your fish for changes in habits and environment.
  • Prevent algae build-up by regularly cleaning.

For further reading, check out this article by Wikihow and read up at Fish Keeping World.