Which parasites are most prevalent in tropical aquarium fish? My article Parasite Surveys of Aquarium Fish, a compilation of 11 different investigations from around the world, answers that question. Freshwater fish (goldfish, guppies, tetras, etc) were sampled from Sri Lankan fish farms, Swedish pet shops, etc. Most surveys reported Monogeneans (i.e., flukes) as the most common parasite of aquarium fish–whether healthy or diseased. For example, 37% of 223 freshly caught wild fish from the Amazon carried Monogeneans, ranging from a 92% prevalence in Angelfish to only 7.4% in Cardinal Tetras. The ICH parasite was in second place (21% prevalence in the 223 fish), but other studies reported a much lower prevalence of the ICH parasite. Overall, Monogeneans dominated.
Successful eradication of Camallanus worms in guppies and other tropical fish using fenbendazole and levamisole
Over the years, I have had to deal with nasty Camallanus worms several times in newly purchased fish. My article ‘Treating Fish for Camallanus and Other Nematodes’ contains step-by-step instructions for preparing a Fenbendazole-containing fishfood that successfully rid my tanks and fish of these intestinal parasites. I have also described treatment using Levamisole HCl, another highly effective drug. Article describes the worldwide presence of Camallanus and the related Capillaria parasite. Photo shows a Camallanus worm slowly being expelled from the anus of a female guppy during the Fenbendazole treatment. (She recovered fine.)