Dictionary of Ichthyology  

MS-222 = a fish anaesthetic applied by immersion in dosed water (tricaine methanesulphonate, methanesulfonate salt or 3-aminobenzoic acid ethyl ester (C9H11NO2 CH4SO3)). A white powder best transported across borders in its original container.

Photograph by Brian W. Coad.

Canadian Museum of Nature
www.briancoad.com