Two groups of juvenile grass carp Ctenopharyngodon idella have been raised within 6 months on animal and vegetable foods (Kasumyan & Morsi, 1997). Carps conditionally named carnivorous have been grown on Chironomidae larvae, carps named vegetarian  on duckweed and Romaine lettuce (Lactuca sativa) leaves, respectively. After conditioning, carnivorous carps show preferences for agar-agar pellets with the Chironomidae larvae extract (75 g w.w. per 1 liter), vegetarian carps  to pellets with the lettuce extract (75 g w.w.). According to Kasumyan & Morsi (1997), carps of both groups do not change specific preferences for individual 21 amino acids and 4 classical taste substances tested.

Generally, gustatory search images form in the memory of fish relatively quickly. In common carp, Cyprinus carpio (Ivlev, 1977), fairly stable visual and gustatory search images in respect of Chironomidae larvae and other natural foods form within 1-2 weeks.

Basic References

Ivlev V.S. 1977. Experimental ecology of the feeding of fishes. Nukova Dumka Publishers, Kyiv

Kasumyan A.O., Morsi A.M.K. 1997. Taste preferences of classical taste substances by juvenile grass carp Ctenopharyngodon idella (Cyprinidae, Pisces), raised on animal and vegetate foods. Proceedings of the Russian Academy of Sciences 357, 284-286