Abstract

Eubacterium tarantellus was previously shown to be associated with fish kills in Biscayne Bay and the Texas Gulf Coast.The organism was primarily isolated from the brains of dead and moribund fish. We postulated that the anaerobe was harbored in a carrier state in the brains of fish and that clinical manifestations were stress associated.

Twenty-four fish species from Biscayne Bay and the surrounding ocean waters were sampled to determine the incidence of E. tarantellus in the brain, liver, kidney, spleen and intestines of clinically healthy specimens. In addition, the number of E. tarantellus per gram of brain tissue was determined for one species.

Thirteen of the species harbored the anaerobe in the brains. Although some specimens had the anaerobe in other organs, the incidence was low; no fish had the organism in other organs if its brain was not infected. Juvenile Eucinostomus gulu brains contained only 20 to 250 bacteria per gram of tissue.

Notes

Blue-green algae and organophosphate toxicity can be causes of large fish kills.

E. tarantellus is a gram positive anaerobe which is nonmotile and does not produce spores.

Growth Range

• 0.5 - 2% salinity

• 5.6 - 8.0 pH

• these were not the environmental conditions where fish kills occurred, therefore it is surmised that the organism was transferred from fish to fish.

 The name "tarantellus" means "a fast, whirling dance", which is a symptom shown by fish infected with E. tarantellus.

The organism was most commonly isolated from the brain and was found in the following species: Bluefish, Sea Trout, Black Mullet, Sheepshead, Lookdown, Sea Bream, Gray Snapper, Pinfish, and Blue Striped Grunt. It was not isolated from the Scaled Sardine, Catfish, Doctor fish, Bonnet-head Shark, Common Seahorse, Margate, Tarpon and Black Margate.

Adult fish tend to have a higher incidence of infection.