How to Treat Parasites in Aquarium Fish

When you buy an aquarium fish, did you know that it has traveled from a fish farm to a wholesaler to a pet store before it got to you? It’s possible that the fish may have contracted an external or internal parasite during its journey. Wild-caught fish can be susceptible to multiple parasites. Most aquarium fish don’t stay in the store long enough for parasitic diseases to be checked. If your fish has visible parasites on its body, a swollen abdomen, skinny disease, hole-in-the-head, or strange-looking, discolored poop, you may need to treat it with one of the following antiparasitic medications.

1. Ich-X

Hikari is known for producing high-quality fish food, but their Pond Solutions and Aquarium Solutions product lines also make excellent fish medicines. After testing dozens ich medicines in the United States we found Ich-X to be the most effective for treating ich, white spot disease, other external protozoan parasites, and mild fungal infections. Ich-X is used to treat all fish entering our fish shop before they are sold to customers. It contains formaldehyde as well as malachite blue chloride. It is safe to use on scaleless fish, invertebrates and live plants.

If your fish looks like it’s covered in little, white grains of salt, it could be ich and needs to be treated immediately. You should always keep first aid medication like Ich-X handy.

There are two types: Aquarium Solutions IchX for small aquariums, and Pond Solutions IchX for larger tanks with 50 gallons and more. Follow these steps to get Aquarium Solutions Ich-X.

1. Perform a water change. Take out any chemicals (such as activated carbon and Purigen) or UV sterilizers. 2. For every 10 gallons of aquarium water, add 1 teaspoon (5ml) of IchX. 3. Each 24 hours, change one third of the tank water. Then, repeat the dose. 4. Continue daily treatment for at least 3 days after you last see any signs of disease.

Pond Solutions Ich-X is stronger than Aquarium Solutions Ich-X, so use the same directions but with a dosing concentration of 1 teaspoon (5 ml) of medicine per 50 gallons of water. You can read the full article to learn more about how to treat ich.

2. ParaCleanse

Fritz ParaCleanse is another well-tested medication that we use to preventatively treat all new fish that enter our retail store, and it can be safely used in conjunction with Ich-X. It is used to treat internal parasites as well as some external parasites like:

Tapeworms (e.g. wasting or skinny disease) – Gill and skin flakes (e.g. Gyrodactylus specie) – Hole-in the-head (HITH), disease (e.g. Spironucleus and Hexamita species)

ParaCleanse has praziquantel for worms and flukes. It also contains metronidazole for certain bacteria and protozoans. It is safe for fish, fish fry (scaleless), shrimp, snails, and aquarium plants. Follow the manufacturer’s recommendations if your fish is suspected to have one of these parasites. Don’t give the medicine half-doses as it may not be effective.

1. Clean the aquarium, and get rid of any UV sterilizers and chemical filtration. 2. On Day 1, dose 1 packet of ParaCleanse per 10 gallons of water. 3. Dosage 1 packet ParaCleanse to 10 gallons of drinking water per day. 4. On Day 5, perform a 25% water change on the aquarium. 5. Wait 2 weeks before administering any other medications so that your fish have a chance to recover and gain weight. You can help your fish pass dead worms by feeding them foods high in fiber and roughage like spirulina brine shrimps, daphnia and algae wafers. 6. After 2 weeks, repeat the 5-day treatment by following Steps 1-4. The medicine does not affect eggs so we must wait for new worms hatch. It takes 2 weeks for internal parasites to be completely eliminated in stores before fish can be sold. 7. [Optional] Repeating the 5-day treatment two times will eliminate the majority of parasites. If you really want to make sure your fish are clean, wait 2 more weeks and repeat Steps 1-4 for a third treatment.

Tapeworms eggs do not react to most medications. We must wait until the new larvae hatch so that we can treat them. We recommend that you redo your tapeworm eggs after they hatch.

ParaCleanse is not very harsh, so multiple treatments are generally safe for your fish. It can be expensive so make sure to put your fish in a smaller tank.

Do you medicate fish’s water or fish’s food? This is a tricky question. Sick fish often won’t eat very much (or at all) because they don’t feel well. It can also be difficult to keep track of how much medication each fish is taking. This could lead to fish consuming too many medications while others are eating too little. Meditated food might be an option for treating one fish, if the fish is still eating well. We recommend that you use medications that dissolve in water to treat multiple animals. This will ensure that each animal receives the correct concentration.

What is the treatment plan for the Quarantine Med Trio? After you have given your fish a 7-day soak with ParaCleanse and Ich-X, follow these instructions, starting at Step 5.

3. PraziPro

PraziPro has a higher concentration of praziquantel, so we recommend using it when ParaCleanse isn’t quite strong enough or if we’re seeing a problem with certain shrimp parasites like Vorticella and Scutalleria japonica.

PraziPro works in a similar way to ParaCleanse. It is safe for fish and invertebrates as well as plants and beneficial bacteria. PraziPro is used primarily to treat flatworms, tapeworms, flukes and turbellarians. These are the steps to use PraziPro:

1. Clean the aquarium, and get rid of any UV sterilizers and chemical filtration. 2. You should shake the bottle and add 1 teaspoon (5ml) PraziPro to 20 gallons water. 3. Allow the medication to rest for 7 days. Then, repeat the process as many times as you like.

Many parasites are found in wild-caught fish and may need three treatments to completely deworm them.

In our personal tanks, we’ve use PraziPro as part of the deworming process for our puffers. First, we treat ParaCleanse for 5 days and then wait two weeks. Then we do a second 5-day treatment of ParaCleanse and then wait a month. The final step is the PraziPro 7-day treatment.

4. CyroPro

Pond Solutions CyroPro was specifically formulated to deal with external parasites like anchor worms and fish lice (e.g. Argulus) Cyromazine, the active ingredient in the product, prevents crustaceans and parasitic insects from molting exoskeletons. This treatment is safe for fish, plants, snails, and insects. However, you might want to remove your shrimp, crab, and any other crustaceans before it can be used.

1. Perform a water change in the aquarium or pond, and get rid of any chemical filtration and ultraviolet sterilizers. 2. Give the CyroPro a good shake and 1 teaspoon (5 ml), per 50 gallons. 3. Change the water and repeat the treatment every 7 days for at least 21 uninterrupted days. If you are absent from a treatment day, restart the treatment.

External parasites such as fish lice (seen in the photo above) and anchorworms can be seen to the naked eye. They are commonly found on pond fish, like goldfish or koi.

The water changes that occur before CyroPro are used to restore dissolved oxygen, remove excess nutrients, and decrease the population of water-borne parasites.

5. Expel-P

Fritz Expel-P is a fast-acting dewormer used to specifically treat parasites such as planaria, roundworms and nematodes (such as camallanus red worms), nodular worms, and hookworms. Infected fish may exhibit signs such as anemia, a swollen stomach, red worms leaking into the anus, rapid breathing, or loss of appetite.

The active ingredient is levamisole hydrochloride (HCl), which causes paralysis and death of the worms, but it will not harm your biological filtration, aquarium plants, invertebrates, or healthy fish.

Fritz ParaCleanse recommends multiple treatments to ensure all eggs hatch. Follow the manufacturer’s recommendations and dosage guidelines:

1. Clean the aquarium and remove any chemical filtration and UV sterilizers. 2. For every 10 gallons water, use 1 packet Expel-P. 3. Do a 25% water change after 24 hours. Make sure to vacuum the substrate using an aquarium siphon. This will remove paralyzed and irritated worms. 4. After 1 week, repeat the treatment to get rid of any new worms that hatched out. 5. Continue the weekly treatments as needed until the worms have disappeared or the fish are regaining weight again.

Bonus: Aquarium Salt

Aquarium salt, which isn’t as effective against internal parasites but is available for external parasites, is a good option. The salt works by dehydrating the parasites to death before the fish (which have more mass and stored water) are affected. For complete instructions, see our full article on how to treat sick fish with salt.