Best Medications for Treating Aquarium Fish Diseases

Kate Barrington
by Kate Barrington

Just like any pet, fish can get sick too. But how can you fight illness in your tank? Here’s our list of the best medications for treating aquarium fish diseases.

When a pet dog or cat gets sick, you take them to the veterinarian. What do you do when your fish get sick? Aquarium fish diseases are more common than you might imagine, especially in tanks where new fish or other aquarium habitants have recently been added. Not only are aquarium fish diseases fairly common, but they can be tricky to treat because anything you add to the tank water in terms of treatment can change the water chemistry.

To help you pick the best medications to treat aquarium fish disease, we’ve assembled a list. Keep reading to learn more about common aquarium fish diseases and what products are best to treat them.

Related: Best Fish Food for Aquarium Fish

Best Medications for Treating Aquarium Fish Diseases

The first step in treating aquarium fish disease is identifying the problem. Take what you’ve learned above and do your own research to figure out what disease is affecting your fish. From there, you can consider some of our top picks for the best aquarium fish medications reviewed below:

1. Editor’s Choice: API Stress Coat

This medication is technically a water conditioner, but it provides other benefits as well. In addition to removing harmful chemicals like chlorine from tap water and making it safe, it also replaces the fish’s protective coating that may have been damaged by stress or disease. This dual-action formula helps reduce fish susceptibility to disease and infection. It comes in a wide range of sizes so you can always keep it on hand. Use this medication when adding or changing water, when adding new fish to the aquarium, or when your fish are sick or injured.

2. Runner Up: API General Cure Powder Medication

Designed to treat a wide variety of parasitic infections, this medication comes in the form of a powder for easy administration. This powder can be used in freshwater and saltwater tanks to eliminate parasitic fish disease symptoms like gill flukes, holes in the head, and swollen abdomen, among others. When symptoms of fungal diseases appear, use two packets of this medication every 48 hours.

3. Best for Ick: API Super Ick Cure

Choose from several sizes of this powerful ick cure that quickly kills the parasite within 24 hours of the first dose – dose every day for five days when symptoms first start occurring. It is for use in both freshwater and saltwater tanks and also adds a slime coat for protection against future disease.

4. Best for Fungus: Kordon Methylene Blue

This aquarium fish medication comes in a 4-ounce or 8-ounce bottle and is designed to treat a variety of fungal infections. It can be used in freshwater and saltwater tanks as an alternative to malachite green. It is highly effective and affordable.

5. Best for Parasites: Seachem ParaGuard

This easy-to-use parasite control contains no formaldehyde or methanol, making it both fish and filter safe. It is also formulated for use without altering the pH levels of your aquarium. This means that it is a safer option than the highly toxic formalin-based medications for those who aren’t comfortable with their use.

It is recommended to for the treatment of a variety of ectoparasites and external fungal/bacterial/viral conditions in exotic fish including ich (white spot), velvet, fin rot and flukes. It is safe for use in freshwater tanks and marine environments; however, it should NOT be used when treating an aquarium that includes invertebrates, crustaceans, corals, or elasmobranchs (such as sharks, rays or skates).

If you are looking to treat a receiving tank for new fish or a hospital tank, this is a great option. It is also recommended for use any time that new fish are introduced to your community freshwater tank.

6. Best Copper: Seachem Cupramine Copper

Intense parasite infections sometimes require a stronger medication and this copper treatment is a great option. Rated for both freshwater and marine use, this medication is effective against a variety of external parasites. It is less toxic to fish than other copper medications and won’t affect filtration.

7. Best Treats: Fritz Aquatics Mardel Copper Safe Treats

If you’re worried about a copper treatment affecting your filter or discoloring your tank water, try this product. This medication is safe for freshwater and saltwater tanks (but shouldn’t be used in reef aquariums) and it treats everything from ick to flukes and anchor worms – and to boot, the live nitrifying bacteria eliminates ammonia and nitrates in the tank, as well. Just be sure not to use this solution with fish species that have a known sensitivity to copper. This medication treats 94 gallons of water.

8. Best for Flukes: Hikari Prazipro for Aquarium

This aquarium fish medication contains

9. Honorable Mention: AquaCura Prazi-Cura Fish Medicine

AquaCura Fish medicine contains genuine praziquantel and has no additional fillers or medicines. It is a great choice to deal with fish with flukes like liver flukes, gill flukes, internal parasites, and worms. The praziquantel is mild to your fish while offering maximum impact on the worms infecting your fish and tank. To use just add 1 gram of Prazi-Cura quick acting powder to every 100 gallons of your tank water. The formula will paralyze and kill the worms while helping your fish shed them safely. This is excellent choice for goldfish, koi, and ornamental fish.

10. Also Consider: API Melafix Bacterial Infection Remedy

Whether you are currently working to combat a bacterial infection in your freshwater tank, or looking for a preventative when introducing new fish, API Melafix is a great option. While this all-natural antibacterial remedy isn’t a ‘fix-all’ for fish problems, it does work for a wide variety of different situations. It contains a natural, botanical tea tree extract and Melaleuca, which both help to heal bacterial infections while also repairing open wounds, damaged fins, and ulcers.

Specific conditions that this remedy is designed to target include open wounds and abrasions, fin and tail rot, eye cloud, pop eye, body slime, and mouth fungus.

To maximize the benefits of this remedy, add it to your water daily for a week to treat existing infections. It can also be added for 3 days when new fish are being introduced to prevent unnecessary infections and reduce the risk of disease outbreak in your freshwater tank or aquarium.

11. Best Salt: API Aquarium Salt

Though technically not a medication, aquarium salt is used to treat a wide variety of aquarium fish diseases. Made from evaporated sea water for all-natural results, this product promotes general fish health as well as gill function and may speed recovery from disease. What’s more, it also improves respiration for fish freshwater aquariums. Use aquarium salt when changing water in the tank, when treating certain fish diseases, or when you’re setting up a brand new freshwater aquarium to start off on the right foot.

Always use caution when treating your aquarium for anything, including disease. Adding chemicals or medications to your tank can change the water chemistry which might have a negative impact on your fish more significant than the disease itself.

The Most Common Aquarium Fish Diseases

Aquarium fish can be affected by a wide range of different diseases, some of which are easier to spot than others. In many cases, the first sign of illness is a change in behavior. If your fish stop eating as much as they usually do or if they are less active than usual, you may want to take a closer look to see if you spot signs of disease.

Here are some of the most common aquarium fish diseases to look for:

  • Body Flukes – Caused by undesirable tank conditions, body flukes are tiny flatworms that eat away at the gills, fins, and skin of your fish.
  • Anchor Worms – Typically introduced to the tank by new fish, anchor worms are actually tiny crustaceans that burrow into the skin and enter the muscles.
  • Dropsy – Typically caused by a bacterial kidney infection, dropsy occurs when the fish becomes bloated and has trouble swimming properly.
  • Ick – Easily one of the most contagious aquarium fish diseases, ich is caused by tiny parasites that look like tiny white spots all over the skin.
  • Fungal Infection – Fish can be affected by fungus on many parts of the body and it often looks like a white cottony growth. Fish with fungal infections are more susceptible to other diseases.
  • Gill Flukes – These are flatworms that measure about 1mm long and typically affect the gills. Fish kept in poor water quality or overcrowded tanks are more likely to get this disease.
  • Fin Rot – Typically caused by a bacterial infection, fin rot can also affect your fish’s tail or mouth. You may notice fading color and fraying of the fins and tail.
  • Lice – You may not think of lice as a problem for aquatic animals, but they can affect fish. You’ll usually see restless behavior and see tiny pale dots crawling on your fish.

Now that you have a better understanding of what to look for in an aquarium fish medications, it’s time to start shopping! Keep reading to see our top picks.

Can aquarium fish get whirling disease?

Yes, freshwater aquarium fish can get whirling disease, although it’s not very common. This condition is characterized by whirling motion brought on by neurological damage and skeletal deformation, which is caused by the myxozoan parasite called myxobolus cerebralis. The symptoms appear approximately 35 to 80 days after the infection, so if you’ve had your fish for more than a few months in the aquarium, chances are that it’s not whirling disease that’s causing their issues.

How do you treat aquarium fish disease?

Aquarium fish disease can be caused by parasites, bacteria, fungi, or a virus – so the method of treating the disease can vary greatly. The first step is determining which type of diseases your fish have and what is behind it, before you proceed with medications. There are a range of products specially formulated to treat most aquarium fish diseases, whether they function as anti-parasitics, antibiotics, or antifungal solutions. As most aquarium fish diseases are closely related to the conditions in the aquarium, you will also have to make a few changes to your usual practices, from switching the water temperature, lighting, or your cleaning routine.

How do you tell if your fish is stressed?

Fish might not be able to communicate, but that doesn’t mean that their behavior doesn’t change when they are stressed – you just have to pay close attention to catch the signs early on. Loss of appetite, unusual swimming patterns, and gasping for air at the top of the tank are some of the easiest symptoms of stress in fish to recognize. Naturally, fish disease can also be a symptom of stress, particularly those that manifest as changes on the gills and body.

Should I quarantine my sick fish?

Absolutely you should – this minimizes spread of infection to other inhabitants of the aquarium and minimizes the damage. Not to mention it lets the affected fish recuperate and receive treatment in peace! Most aquarists isolate sick fish in a separate tank and treat it with proper medications, and continue that process for at least 2 to 4 weeks before returning the fish back to the main tank.

How long should a fish stay in a hospital tank?

It depends on the sickness you are treating. For most, 2 to 4 weeks will be plenty of time to isolate a sick fish, but sometimes, it’s 4 to 6 weeks at least before the fish gets better and can be returned to the tank. If you are unsure, check what the aquarium medication label says – your fish should be isolated in the hospital tank as long as they are being treated.

What should I consider when choosing medications for aquarium fish?

The goal is to properly identify the problem first, so you’d know what type of aquarium fish medication you’ll need to effectively solve the issues your pets are having. One you narrow down the list and find out which type of disease is affecting your fish, go for medications formulated specifically for that issue – it can be parasitic, viral, bacterial, or fungal in nature. After that, there’s not much to it: just follow the instructions on the package and hope for the best. Of course, it goes without saying that you should always isolate the fish and clean the tank to prevent potential contamination and the spread of diseases.

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Kate Barrington
Kate Barrington

Kate Barrington is the loving owner of two cats (Bagel and Munchkin) and a noisy herd of guinea pigs. Having grown up with golden retrievers, Kate has a great deal of experience with dogs but labels herself a lover of all pets. Having received a Bachelor's degree in English, Kate has combined her love for pets and her passion for writing to create her own freelance writing business, specializing in the pet niche.

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