Conditioned food aversion in the goldfish, Carassius auratus

Naive goldfish (strain Pearl) readily accepted food particles flavored with 2-phenylethanol or vanillin but avoided such particles after association of the conditioned stimulus with illness induced by lithium chloride injection. This conditioning was effective providing the toxicant dose evoked strong intoxication. The conditioned aversion was well expressed up to 47 days after learning. This reaction was revealed only if the food particles were flavored but not when unflavored food was presented in a diffuse stimulus cloud. Temporal blocking of the nostrils in the learned fish significantly decreased the aversion but did not abolish it completely. Thus, both non-nasal chemoreception and olfaction take part in initiation of the conditioned food aversion. On the whole, the conditioned food aversion in this fish is rather similar to analogous phenomenon in mammals.