Successive Negative Contrast Effects for Activity-Conditioned Goldfish (Carassiusauratus) as a Function of Housing Conditions

Abstract

Young goldfish were individually housed in large containers (Part 1), individually housed in small containers (Part 2), or housed in large containers in groups of five (Part 3). The fish were run in sets of five fish (five fish simultaneously in an activity-conditioning chamber). Thus, the fish had to compete for the large or small US that was dropped in the water following a 10-sec. CS (light). Fish in each part comprised groups LS (large US in the first phase of training and small US in the second phase of training), LL, SL and SS. All LS groups showed downward shifts in activity and negative contras effects (lower activity levels than SS control fish). None of the SL groups produced complete upward shifts in activity. Group-housed fish in Part 3 showed larger increases in activity to the CS than individually housed fish in Parts 1 and 2.