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. We have years of experience in helping customers at the fish shop and online. Here are the steps we follow and the medications we use to bring our fish back to good health as quickly and efficiently as possible.


Step 1: Do you have a Quarantine tank?

A quarantine tank is an aquarium that contains only new fish. This allows you to ensure that your fish are healthy and won’t infect other fish. But you may say, “I don’t need a quarantine tank for my new fish because they all look healthy. Why is it possible that sickness can come from fish with no symptoms? This is because while the original host fish might have an illness or other conditions, its strong immune system keeps the disease under control. The infection can spread from the aquarium to the other fish if the host fish becomes stressed out by the new environment.

The truth is that when fish come in from a wholesaler, breeder, or fish store, they’re most likely bringing in some kind of pathogen. Any place that keeps a lot of fish together has a higher risk of having fish diseases. If you purchase fish, or get them from a friend who is a fish-loving person, don’t immediately place them in your aquarium. Instead, the best practice is to set up a quarantine aquarium where you can first observe the fish for symptoms and treat them with preventative medications. (This is similar to how we vaccinate new dogs and cats to prevent common disorders from spreading.) This will not only prevent contamination from spreading, but also save money and reduce the risk of losing your life.

This is often a sign of many disorders. 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: Are You Able to Identify the Problem?

Fish keepers, especially beginners, are often unaware of what is ailing their fish. However, it is not productive to ignore the problem. Ideally, we want to treat the issue as soon as possible to give the fish the best chance of surviving. We recommend that you use broad-spectrum medicines for parasitic, fungal and bacterial infections to cover all bases. There are many medications that can be used around the globe. These medications will provide effective protection for most conditions. They are safe to be used with shrimp, snails and baby fish.

After consulting with ichthyologists and spending tens of thousands of dollars in development time and extensive testing, we narrowed down the search to three medications – Mardel Maracyn, Aquarium Solutions Ich-X, and Fritz ParaCleanse. These medications can be used together and, in our experience, will not cause harm to beneficial bacteria in your aquarium.

Descriptions of the three-part quarantine medication trio

A lot of people ask, “I have two out of these three medications. Is it OK to swap one of these medications for another? Unfortunately, some medications can be toxic together. That is why licensed pharmacists in humans are trained to identify and prescribe only safe combinations. Similarly, we have no way of knowing the compatibility of other fish medications without thorough testing, and there are countless types of medication on the market (some of which are only available 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’re certain about the disease of your fish, first treat it with the correct medication. Follow the manufacturer’s instructions or packaging. For example, if you see fish fungus, read our full article and consider using Maracyn and Ich-X. ParaCleanse is recommended for tapeworms and other parasites. It should be repeated every two to three months to kill any eggs still in the hatching fish.

Trio de quarantine medicines

However, if you need to quarantine fish, or if you are unsure about the ailment, all three medications can be used simultaneously. Oftentimes, a fish may start off with one type of illness, such as a fungal infection. This can lead to an open wound, which could make the fish more susceptible to secondary bacterial infections. To give your fish the best chance of healing, treat all three types of infections.

1. If you are treating new fish, make sure the quarantine tank is far away from your normal display tank, and do not let the tanks share any nets, siphons, buckets, or other equipment. Since droplets of water can travel on your hands to another aquarium, make sure to thoroughly wash your hands and arms with soap and hot water between tanks. 2. To ensure that your fish are in a healthy environment, you should clean the tank thoroughly before beginning treatment. Wipe the aquarium walls so that you can easily observe the fish’s condition, clean out the waste in your filter, and use a siphon to vacuum the substrate and change the water. 3. Turn off any UV sterilizers and remove any chemical filtration, such as Purigen or activated carbon. Some medications can affect the water’s viscosity, which can cause problems for fish’s breathing. 4. Do not dose according to the box instructions. 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 does not stain aquarium decorations in our experience, but be careful not to spill it because it can stain your skin or clothing.) 5. Allow the fish to soak in the medication for at least one week. Do not feed or change the water for the next week. (If you feel you must feed your fish, wait until Day 4 or 5, and only feed them very lightly.) You should keep the aquarium filter and heater on during this time. Also, aquarium lighting will not deactivate the medication. 6. After one week passes, you should change out 30% water in your aquarium. Continue feeding your fish and monitor for changes in symptoms.

If you have very weak fish, it may be easier on their bodies to space out the treatment. Bacterial infections tend to be the most common. For a week, use Maracyn at the dose 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 should be administered in the third week for gill flukes and internal worms.

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). Once the ich is beaten, wait a couple of weeks with no medication to give the fish a break, and then follow up by treating with the other two quarantine medications (e.g., Maracyn and ParaCleanse) for 1 week as originally suggested.

You may want to treat all fish in your home, even if they are not familiar with the treatment. Then proactively treat all new fish that enter your home so that nothing slips through. Yes, medication can be expensive, but pathogens can lie dormant for a long time, waiting for the chance to take over your fish’s immune system if they get stressed or we lapse on tank maintenance. These medications should always be available for emergency situations, based on our own experience. There is a good chance that they won’t be available at your local pet shop. You will need to wait several days before you can order them online or settle for a brand that doesn’t work.

You can play an active role in the health of your fish

We are very passionate about quarantining all new fish, no matter who you get them from, because even changing their environment (e.g., different water parameters or new social hierarchy) can trigger 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.