An Analysis of Common Disease Types in Coral Reef Fish

Signs of infection The fish may rub against hard objects. On close inspection, a fog-like film may be found on the fish's skin, the gills may be inflamed, and affected fish show typical rapid gill movements. Among affected fish, many species of marine fish have been found to suffer from this disease.

Details of the infection Oodinium ocellatum is a parasitic single-celled organism known as a dinoflagellate. Careful examination of it requires a microscope with 3000x magnification. Oodinium ocellatum is similar to Oodinium pillularis, which causes freshwater velvet disease, but in the early stages it tends to invade the epithelium of the gills rather than the fish's body. When the parasite matures, it falls to the bottom and forms a cyst. The cyst ruptures and releases free-swimming dinospores, which can live for 72 hours before attaching to a suitable host fish. At temperatures of 20-25°C, this disease is most likely to become epidemic among tropical marine fish.

Recommended treatment Specialized medications containing various copper compounds are very effective, especially when there is no coral bed filter medium that absorbs copper. Unfortunately, copper is particularly toxic to invertebrates. Use new antiparasitic treatments as alternatives, but carefully check the instructions, because most treatments are harmful to invertebrates such as sea anemones, corals and crustaceans.