Freshwater Fish Lice

fish lice

There are many parasitic crustaceans throughout the fish kingdom, the one most commonly seen in pet fish is Argulus ssp., also known as “Fish Lice.” Under the microscope, they are one of the strangest looking parasites you will come across.

These parasites are found in salt and freshwater all around the world. We do see them in many pet species of fish. Fish lice have stylet that punctures the host fish to feed on body fluids (yum!). This causes extensive skin irritation and severe infestations can infect the gills and kill fish. Due to the penetration, secondary bacteria and fungi can also infect your fish.

What is the best treatment for fish lice?

Treatment of fish lice requires some serious drugs, some of which are not available in certain states. Prior to starting treatment, make sure your water quality is within range and there are no secondary infections to worry about. Many over the counter medications are only effective at treating juvenile stages, not adults. Our office has seen many severe infestations that take hours to remove all of the lice present.

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2 thoughts on “Freshwater Fish Lice”

  1. Dianna Burton

    Hello Dr’s,
    This question is about anchor worm. Unfortunately I am unable to meet with you in person because I live on the east coast in Baltimore, MD. I have a betta fish that I purchased in December 2021. I recently saw some tiny, clear swimming things in his tank. I have done hours of research online, and found out that they are juvenile anchor worms. After learning that, I used a magnifying lens to closer evaluate my fish. So far I have found 1 anchor worm attached near his right pectoral fin. Ugh! Poor guy. I have been making every effort to keep his tank parameters in check, and keeping his tank clean. I suspect they were introduced to his tank on new pplanes unless he came with them when I bought him. He is still eating 3 Hikari Bio-Gold baby pellets twice daily. Because he has been under the weather, I have started adding Vita-Chem multi-vitamin drops to his food when soaking the pellets in tank water. I have also added 2 tbsp of aquarium salt to my 10 gallon tank. I have a sponge filter. I also recently provided him with a hldeout to reduce his stress, and there are several plants floating in his aquarium. I talk to him multiple times each day. There is so much information online, and I’m not sure how accurate it is. To my knowledge we do not have any fish veterinarians in MD. I do not want to harm my fish. Please help me treat my fish. His name is Thailand, or Thai for short.
    Thank you,
    Dianna Burton, DVM

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