How to Treat Sick Aquarium Fish (even if You’re Not Sure What’s Wrong)

How to Treat Sick Aquarium Fish (Even If You’re Not Sure What’s Wrong)

Treating a sick aquarium fish can be difficult, especially if you’re new to the hobby or have never seen this disease before. Based on years of experience helping customers at our fish store and online, here are the step-by-step guidelines and medications we personally use to get our fish back to health as quickly as possible.


Step 1: Do You Have a Quarantine Tank?

A quarantine aquarium is a small, empty tank that you use to hold new fish until they are ready for your main aquarium. This allows you and your fish to check that they are healthy before adding them into your main aquarium. But you may say, “I don’t need a quarantine tank for my new fish because they all look healthy. It is possible to get sick from fish that have not been ill. This is because although the fish’s original host may have an illness, their strong immune system keeps it under control without any visible symptoms. It is possible for the disease to spread to other fish by stressing the host fish when it is added to an aquarium.

It is most likely that fish are brought in by a wholesaler or breeder from fish stores. Fish diseases are more common in places that keep a lot of fish. If you purchase fish, or get them from a friend who is a fish-loving person, don’t immediately place them in your aquarium. A quarantine aquarium is a good idea. This will allow you to first examine the fish for signs and then administer preventive medication. This is similar in practice to how we vaccine new cats and dogs to stop common diseases spreading. This prevents contamination and will save you money over the long-term.

This can be a sign that the fish is lethargic. Their chances of quicker recovery are increased if they are kept in a secure environment and away from other fish.

A majority of people don’t have a quarantine tank. They’re either new to the hobby and/or think it’s too complicated. But it only takes one severe outbreak to realize the importance of having one. We recommend that you treat the entire aquarium with medication if a disease has been introduced to it.

Step 2: How can you identify what’s wrong?

Many fish keepers, especially novices, don’t know what has happened to their fish. But, not only is it not productive, but they also may not be aware of the cause. To give your fish the best chance of survival, it is important to address the problem as soon as possible. Therefore, we advise covering all your bases by using broad-spectrum medications for bacterial, fungal, and parasitic infections. There are many medications that can be used around the globe. What medications are safe for use with fish, plants, shrimp, snails, baby and sensitive fish without scales?

After speaking with ichthyologists, spending thousands of dollars on development and extensive testing, the search was narrowed to three medications: Mardel Maracyn and Aquarium Solutions Ich-X. All of these medications are safe to use with each other, and in our experience, they will not harm the beneficial bacteria in your aquarium.

Description for the trio of quarantine medications

A lot of people ask, “I have two out of these three medications. It is okay to replace one of these medication with another brand. Unfortunately, some combinations of medications can prove toxic. This is why licensed pharmacists are trained to only prescribe safe and effective drugs. Without thorough testing, we don’t have the ability to determine if other medications will work well together. Additionally, there are many different types of medication that are available on the market, some only in certain countries. We also do not know if these unknown products are safe for all fish, invertebrates, plants, and beneficial bacteria.

Step 3: How to treat your sick fish

If you know the exact disease that your fish is suffering from, make sure to treat it immediately with the right medication. If you suspect fish fungus, please read our article and consider Ich-X or Maracyn. ParaCleanse can be used to detect tapeworms and other internal parasites. You should also treat the fish every two to three weeks for any eggs that may have hatch.

Trio of quarantine medications

If you have to quarantine new fish, or you don’t know what ailment it is, you can use all three medications simultaneously. Oftentimes, a fish may start off with one type of illness, such as a fungal infection. This can leave the fish vulnerable to secondary bacterial infections. Thus, it’s best to treat for all three types of infection to give the fish the greatest chance of recovery.

1. When treating new fish, be sure to keep the quarantine tank away from the main display tank. Do not share your tanks with siphons, buckets, nets, or any other equipment. You should wash your hands with soap and hot tap water after handling water droplets. 2. If you are treating the entire display aquarium, do a thorough cleaning of the tank to make sure the fish’s environment is optimal and free of any stress factors before starting treatment. You can inspect the fish’s condition by wiping the aquarium walls. 3. Remove any chemical filtration (such as activated carbon or Purigen), and turn off any UV sterilizers you may be using. Consider adding extra surface agitation (such as with a simple air stone and air pump), since some medications can change the water’s viscosity and hamper with the fish’s breathing ability. 4. Do not use the box directions. Instead, add 1 packet of Maracyn, 1 packet of ParaCleanse, and 1 U.S. teaspoon of Ich-X for every 10 gallons of aquarium water. (Ich-X is not known to stain aquarium decorations. However, it can stain clothes and skin if spilled. 5. For one week, let the fish soak in their medication and then do not feed or change water. If you feel the fish must be fed, wait until Day 4/5 or 5. Then feed them only lightly. During this time, keep the aquarium heater and filter on. Also, aquarium lighting will not deactivate the medication. 6. After one week, you can change 30% of the aquarium’s water. Keep the fish hydrated and keep an eye on any symptoms.

You may find it easier to give the treatment to very weak fish. Bacterial infections are the most common, so use Maracyn first for a week (at the dosage recommended in Step 4). Ich and external parasites are the second most common, so next treat the fish with Ich-X for a week. ParaCleanse is recommended for the third week to treat internal worms or gill flukes, which are slower-acting parasites.

If it is possible to identify the illness (such like ich), you should switch to the right medication and complete the remainder of the quarantine medicine trio.

When you start the quarantine medication treatment, a few days later you may see obvious signs of an outbreak like ich (or white spot disease). You should change 30% of the water and follow the manufacturer’s instructions (e.g. IchX in this instance). Wait a few weeks to let the ich die. Then, treat the fish with ParaCleanse or Maracyn for a week.

You may want to treat all fish in your home, even if they are not familiar with the treatment. Make sure you are proactive with any fish that comes into your home. While medication is expensive, some pathogens may remain dormant for years, just waiting to attack your fish’s immune system. We recommend that you always have these medications available in an emergency. This is based on our personal experience. Chances are that you won’t be able to find them last minute at your local pet store and will have to either wait several days to receive an online shipment or settle for an untested brand that may not work at all.

Play an active role in your fish’s health

We are passionate about quarantining any new fish, regardless of where they come from. Changes in their environment, such as new water parameters or social hierarchy, can cause disease. Every fish we receive is pre-medicated and given a clean bill before they leave our care.

In the same way, take the proper precautions to ensure your own fish can lead long and healthy lives.

Are you dealing with a specific sickness in your aquarium fish? You can find detailed instructions in our article list.