Attempting to tame an ocelot results in the first fish being accepted, enabling breeding mode. Subsequent fish result in no particles or taming. The number of fish held in the player's hand will appear to decrease when used, even disappearing when all fish are used, but clicking on the inventory slot holding the fish causes them to reappear.

Every so often a fish is actually accepted with hearts, but this results in breeding mode, not taming. I went through a full stack of fish this way, but no taming occurred.