A study of ectoparasite on snakeskin gourami (trichogaster pectoralis) and morphology of trichodinid

Abstract

This is a study on ectoparasites of Snakeskin gourami, Trichogaster pectoralis. The objectives of this study were the observation of ectoparasites which infected the fish and establish morphological studies of Trichodina sp. Fishes were bought from Pasar Tani, Kuala Terengganu, Terengganu and thirty fishes were observed and diagnosed at Biodiversity Lab, Universiti Malaysia Terengganu. In this study, skin and gill smears were made for observation of parasites. Trichodinids and Monogenean were found. The samples were mounted on the slide and observed under microscope to identify parasite. Gyrodctylus sp. and Trichodina sp. were found on skin smears. Gyrodactylus sp. has two main anchor hooks and opisthaptor with 16 marginal hooks. A pair of anchor hooks were joined by a pair of dorsal and ventral bars. This species have no eyespots and short oesophagus. In the middle of body has uterus with embryo. Trichodina sp. has proteinaceous cytoskeleton of the adhesive disc consists of a ring of hollow conical elements with flat lateral projections, known as denticles. Slide glass containing Trichodina sp. were air dried. Then, the dried slides were submerged into 1 % of Silver nitrate, rinsed with distilled water and placed in Petri dish which filled distilled water. A piece of white paper was placed under Petri dish and exposed to sunlight for 3-4 hours. The sunlight will oxidize the silver nitrate to change into black colour. Ten samples of Trichodina sp. that were found were drawn on tracing paper. The measurements of morphology Trichodina sp. were done to compare with other Trichodina that have been studied based on number of denticles, number of radial pins and other characteristics of morphometric measurements. The measurements of this Trichodina sp. did not match any of the species described hence is could be a new species.