Reproduction of Ichthyophthirius multifiliis (Ciliata, Ophryoglenidae)

A case of reproduction of Ichthyophthirius multifiliis in the superficial tissues of larvae and fry of Amur wild carp is described. At a temperature of water from 28 to 29 degrees trophonts of Ichthyophthirius encysted on fishes. Inside cysts repeated cell division occurred but this process did not result in swarm spores formation. Later on with the increase of temperature to 29.5--31.5 degrees cysts degenerated.