How to Spot Diseases in Your Fish Tank

When your fish get sick, treating the correct disease is the key to a quick recovery. Learn how to spot some of the most common freshwater fish diseases, and what to do to cure them.

If you keep freshwater aquarium fish, you will find that they will get sick from time to time. There are a variety of reasons for fish to get sick. A change in water quality can cause them to be more susceptible to disease. Introducing new fish or new water to a tank can introduce a disease to the water. Fish who have been in a fight and have an open wound are also vulnerable to disease.


One common disease for freshwater fish is ich. Ich makes the fish look as though it has been sprinkled with salt. The disease appears as tiny white dots all over the fish's body. The fish will often rub and scrape against aquarium décor. Ich is a highly contagious parasite, so if you notice ich in your tank, you need to treat the entire tank immediately.

Even if only one fish is sick, the rest of them have been exposed, and treating the entire tank will kill the parasite before more fish succumb. Ich can eventually be fatal, so take care of it as soon as possible. It can be treated with over-the-counter water treatments.


Another common disease in freshwater fish is fungus. Fungus can look like a white slime or white mold-like puffs on the fish's body. Like ich, fungus might also cause the fish to scrape against aquarium décor. If left untreated the fungus will eventually eat away at the skin of the fish and kill it. Fungus is also contagious, and can be treated by over-the-counter water conditioners.

Clamped Fins

Clamped fins are another common problem you might notice in your fish tank. This is an indication that fish are getting sick. If you notice fish with clamped fins, then thoroughly clean your tank. Clean the gravel and do a one quarter water change.

There is a product on the market called Quick Cure that is great for just about any disease, and since clamped fins can be an indication of many problems, after you have cleaned your tank, add the appropriate amount of Quick Cure. Add some aquarium salt to the tank. These steps should kill whatever is bothering your fish.

Open Sores

You may notice that a fish has a sore on their body. This can happen because the fish was in a fight with another fish, or because it brushed against something sharp in the tank. Quickly take action if you notice a sore because it will make the fish vulnerable to infection. Follow the same treatment steps as you do for clamped fins. This will help speed up the healing process before an infection can set in.

Gasping at the Surface

If you notice your fish gasping at the water's surface, it does not mean that the fish is hungry. It means that the fish does not have enough oxygen in the water. Check your filter to make sure it is functionally properly. Fix it if it needs to be fixed. Then check the temperature of the water. Also, inspect the surface of the water for oil or other problems that could be harming the quality of the water. If none of these things are the problem, add some aquarium salt and water conditioner.

Don't Wait!

Taking immediate action when you notice a potential problem can help keep your fish from getting more serious and harder to cure diseases. Do not take your fish's health lightly.

Remember, they are counting on you for everything in their environment.

Make sure it is safe and healthy!