Efficacy of sea salt, metronidazole and formalin-malachite green baths in treating Ichthyophthirius multifiliis infections of mollies (Poecilia sphenops)

摘要

Ichthyophthirius multifiliis is an obligate fish parasite with devastating consequences for wild and captive fish stocks. In the current study, we compared the efficacy of three treatments, sea salt, metronidazole and a mixture of formalin and malachite green, against an I. multifiliis outbreak observed in a stock of mollies (Poecilia sphenops) held by an aquarium retailer. The quickest recovery was observed in fish treated with sea salt, with no visible trophonts after 3 days at 27 degrees C. After 6 days in a continuous bath treatment, the mean prevalence and parasite intensity were also significantly reduced in fish treated with the formalin-malachite green combination compared to metronidazole-treated fish. Our results indicate that metronidazole baths are not effective against I. multifiliis, and that a sea salt bath should be the treatment of choice for mollies.