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? That means that there’s a high likelihood that it may have picked up some kind of internal or external parasite along the way. Wild-caught fish are more likely to have multiple parasites. Most aquarium fish don’t stay in the store long enough for parasitic diseases to be checked. You may need to use one of these antiparasitic medication if your fish is showing signs of parasitic disease: a swollen stomach, thin disease, hole in the head, unusual-looking, discolored stool, or swollen abdomen.
1. Ich-X
Hikari is well-known for their high-quality fish foods, but they also produce excellent fish medications under their Aquarium Solutions and Pond Solutions product lines. We have tested dozens of ich medications in the United States and found that Ich-X is the best for treating ich (or white spots disease), as well as 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 has two active ingredients, formaldehyde & malachite-green chloride. It is safe for scaleless fish and invertebrates as well as live plants.
If your fish appears to have a lot of white salt crystals, it may be ich. 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. These are the steps to use Aquarium Solutions IchX
1. Do a water change and clean the aquarium. Take out any chemicals (such as activated carbon and Purigen) or UV sterilizers. 2. Dose the aquarium with 1 teaspoon (5 ml) of Ich-X per 10 gallons of water. 3. Each 24 hours, change one third of the tank water. Then, repeat the dose. 4. You should continue daily treatment at least three days after your last sign of illness.
Pond Solutions IchX is stronger than Aquarium Solutions IchX. Therefore, follow the same instructions but use a dosing ratio of 1 teaspoon (5 ml of medicine) per 50 gallons. For more details on how to recognize and treat ich, read our full article here.
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., skinny or wasting disease) – Gill and skin flukes (e.g., Gyrodactylus species) – Hole-in-the-head (HITH) disease (e.g., Hexamita and Spironucleus species)
ParaCleanse includes praziquantel, which is used to treat worms or flukes. Also, metronidazole is used to kill certain bacteria. It is safe for scaleless fish, fish fry, snails, shrimp, and aquarium plants. You should follow the manufacturer’s instructions if you suspect that your fish may have one of these parasites. Do not give half the recommended doses or the medicine might not work.
1. Clean your aquarium and get rid all chemical filtration or UV sterilizers. 2. Dose 1 ParaCleanse packet per 10 gallons water on Day 1. 3. On Day 3, dose 1 packet of ParaCleanse per 10 gallons of water. 4. On Day 5, perform a 25% water change on the aquarium. 5. You should wait for your fish to gain weight and recover before giving them any other medications. 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. Follow Steps 1-4 for a 5-day repeat treatment after two weeks. 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] Doing the 5-day treatment twice gets rid of 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. That is why we recommend redosing after 2 weeks once they have hatched.
ParaCleanse is not very harsh, so multiple treatments are generally safe for your fish. However, it can be a little expensive on the wallet, so try putting your fish in a smaller quarantine tank so that there is less water volume to dose.
Do you medicate fish’s water or fish’s food? This is a tricky question. Because they are sick, sick fish will often not eat as much or as often as normal. Also, it can be hard to monitor how much medicated food each fish is getting, so some fish may be consuming too much medicine while others are consuming too little. Meditated food might be an option for treating one fish, if the fish is still eating well. If you are treating multiple animals, we recommend medications that dissolve in the water and treat the whole tank so that we can ensure every animal gets the right concentration.
How does this treatment plan work with the quarantine med trio? If you have proactively treated your new fish with a 7-day soak using ParaCleanse, Ich-X, and Maracyn, then follow the above instructions starting with Step 5.
3. PraziPro
PraziPro has higher levels of praziquantel. It is recommended to be used when ParaCleanse may not be strong enough, or if you are experiencing problems with certain shrimp parasites, such as Vorticella japonica 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 your aquarium and get rid all chemical filtration or UV sterilizers. 2. Shake the bottle well and dose 1 teaspoon (5 ml) of PraziPro per 20 gallons of water. 3. Let the medication sit for 7 days. Repeat the dosage as necessary, but no more than once every 3 days.
Wild-caught fish often contain lots of parasites that may require three rounds of treatment to fully deworm.
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. As our final deworming step, we apply 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. It is safe for plants and fish. However, you should consider removing any shrimp, crayfish or other crustaceans prior to treatment.
1. Make sure to water change the aquarium and pond. Also, get rid of all chemical filtration or UV sterilizers. 2. You should shake the bottle and add 1 teaspoon (5ml) CyroPro to 50 gallons water. 3. Change the water and repeat the treatment every 7 days for at least 21 uninterrupted days. If you miss a day of treatment, you can restart the treatment.
External parasites, such as fish lice (seen below) and anchorworms, are easily visible to the naked eyes and can often be found on pond fish such as goldfish and Koi.
The water changes before each dose of CyroPro helps to refresh dissolved oxygen levels, remove excess nutrients, and reduce the population of water-borne parasites.
5. Expel-P
Fritz Expel-P, a fast-acting, dewormer, is used to treat parasites like roundworms, planaria, nodular and hookworms. Symptoms in infected fish can include an emaciated body, swollen abdomen, red worms leaking out of the fish’s anus, loss of appetite, or rapid breathing.
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 is a multi-treatment program that ensures all eggs are hatched. Follow the manufacturer’s recommendations and dosage guidelines:
1. Clean the aquarium, and get rid of any UV sterilizers and chemical filtration. 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. You can repeat the treatment once more worms have hatched after one week. 5. Continue the weekly treatments as needed until the worms have disappeared or the fish are regaining weight again.
Bonus: Aquarium Salt
If you do not have access to these medications, aquarium salt is useful for the treatment of external parasites (but isn’t as effective for internal parasites). 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.