PURPOSE: To obtain an organism stick-proofing agent having activity of preventing aquatic fouling organisms from adhering to the surfaces of ships, marine structures, bridges, etc., containing as an active-ingredient a specific low-toxic compound as a substitute for tin compounds, and to obtain an antifouling coating containing this agent.

CONSTITUTION: This organism stick-proofing agent contains as an active ingredient a compound expressed by the formula [X is N or C-Y (Y is NH2, NO2, SO3H, CHO or COOH); R is a 1-20C hydrocarbon or alkoxy]. As the compound of the formula, compounds of the formula in which R is a 6-12C hydrocarbon or alkoxy, or R is bound to the para site relative to X are preferable, being e.g. 4-hexylpyridine, 4-octylpyridine, 4-nonylaniline, 4-octylbenzenesulfonic acid, 2-octylbenzoic acid. When this agent is to be applied, one or more kinds of this compound of the formula may be directly used as it is, but in general is/are used as a dispersion in a suitable binder resin such as butyral resin or acrylic resin.