Trichodina spp.
Introduction
Trichodina species are ciliated protozoan parasites of marine and freshwater species of fish. In large numbers they can cause skin and gill disease and can ultimately lead to the death of the fish.
The organisms are saucer-shaped and have a prominent denticular (tooth-like) internal cytoskeleton ring.
Life Cycle
Certain species of Trichodina live in salt, brackish or freshwater areas. Some have a preference for the gill, some for the skin, and some parasitise both.
Trichodina species reproduce by simple binary fission. Most species are host specific and presumably spread from fish to fish by incidental contact between susceptible host fish, as well as through contact with the organism in the water column.
Clinical Signs
Infected fish may 'flash' in an attempt to scratch off the organisms. Superficial white lesions may appear on the body and the fins may become frayed.
Scales may loosen and opportunistic bacteria may lead to secondary infections causing ulcerations and erosions.
Fish may show respiratory compromise from damage to the gills.
Diagnosis
Water quality parameters should be obtained for a base-line examination.
Skin scrapes of mucus from the skin surface may reveal rapidly spinning ciliated organisms.
Gill, fin and skin biopsies can also be examined and will reveal the organism.
Treatment
As the life cycle is direct, a single treatment is usually adequate.
Chemical treatment is most commonly used: a formalin bath or a salt bath, copper sulphate or potassium permanganate.
Flushing the system may help reduce infestation levels.
| Trichodina spp. Learning Resources | |
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Ornamental Fish Q&A 19 |
References
Lim, C. (2001) Nutrition and Fish Health Routledge
Rosenthal, K. (2008) Rapid review of exotic animal medicine and husbandry: pet mammals, birds Manson Publishing
Leitritz, E. (1980 Trout and Salmon Culture ANR Publications
Tucker, C. (1990) Channel Catfish Farming Handbook Springer
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