Caring for Sick Fish

Just like humans, fish can be susceptible to disease. Bacteria and parasites are contagious among fish that share an aquarium, and diseases can also stem from poor water conditions. So how do you know if your fish is sick, and how do you determine the proper remedies for its condition? Learning to recognize when fish need special care and how to treat them is key to a thriving aquarium!

Sometimes, if your fish is acting strangely, it may be the result of an environmental stressor that can be easily fixed in your aquarium when you know what to look for. This is why it is important to test your water to ensure the water parameters are correct. Use the API FRESHWATER MASTER TEST KIT or the API SALTWATER MASTER TEST KIT to measure the pH, ammonia, nitrite, etc. in your tank. Conditions which can trigger illness include poor water quality, poor diet, and improper water temperature. When fish are weakened or stressed, they will be unable to fight off infections, and could become ill.


If you’ve already confirmed that the water conditions in your tank are correct, there are a few additional warning signs you will notice if your fish still seems unwell, and since you can’t easily take your fish to the vet, it is necessary to diagnose your fish based on its symptoms and treat accordingly. You will first need to determine whether your fish has a fungal, bacterial, or parasitic infection, as all of these will require different treatments. Do you notice white spots on your fish, or is it scratching against the gravel and aquarium ornaments? Your fish likely has Ich, a bacterial infection, which is best treated using API MELAFIX® or API LIQUID SUPER ICK CURE. Are there small grooves or holes suddenly present on your fish’s head, or do you notice any gill or skin flukes? These could be signs of a parasitic infection, and can be treated with API GENERAL CURE for symptoms like these. Are your fish’s eyes suddenly cloudy, or do you notice excessive slime on their skin? You will want to select API PIMAFIX® for these symptoms.

Once you have diagnosed your fish with a particular disease, separate the diseased fish from any healthy fish in your tank until it has completely recovered – otherwise, you risk infecting your entire aquarium community. If separation is not feasible, then treating the entire aquarium is advised.

It’s important to keep your aquarium clean to reduce your fish’s chances of disease or infection. General fish health can be supported by the addition of API AQUARIUM SALT, which aids distressed fish by adding electrolytes and promoting healthy gill function to help fish breathe easier. Additionally, proper feeding with a quality fish food and some basic proactive care will help ensure that the nutrition you provide and environment your fish swim in are at their best.

View our API Diagnosing and Treating Sick Fish Chart here.

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