Materials and Methods

Abstract

The species studied are listed in Table 1 according to their systematic position. This table also contains short notes about habitat, origin, number, and age of the experimental animals. Based on their origin, several groups may be distinguished: The major object of this study, Nannacara anomala, was obtained either by breeding in the laboratory or from local pet shops. Other aquarium fish like goldfish and piranha also were purchased from pet shops. Brook trout yearlings were provided by the provincial fish hatchery at St. Faustin (Québec, Canada). The two hiodontid species were caught alive in the north of the province of Québec, in the lake of Montigny. The group of tide pool-fishes comprises an ecologic community from rocky areas of the Brasilian coast. These species were caught by Prof. M.A. Ali by seining at the Instituto de Biologia marinha of the Uni-versidade de São Paulo (Brasil).