Fish are placed singly into place-preference setup, and the time spent on each side of the tank is recorded. These areas are defined using a programme that can videotrack the fish’s position. Adult fish that are allowed to swim freely in this setup spend roughly 70% of the time on the brown side of the tank, and 30% of the time on the white non-preferred side of the tank. Bold fish should spend more time on the non-preferred (white) side of the tank.
The tank is home-made, by covering the outside of a standard transparent plastic fish tank (approx. 20 high x 25 wide x 30cm long) with coloured paper. One side of the tank is white (the non-preferred side), and the other brown (the preferred side). We use white printer paper for one side, and brown envelope paper for the second side. Two black paper spots, 5cm in diameter, are placed in the middle of the white area of the tank. The tank is filled with 10L system water and light from both below (infrared light) and above (white light). All experiments were conducted in the afternoon (1pm onwards).
1) In this experiment, the amount of time spent on either side of the place-preference tank is recorded using commercially available videotracking software. We have used Zebralab from ViewPoint, but other companies also provide suitable software.
6) Appropriate statistical tests should be used to analyse the data. For a comparison of two genotypes, a T-test may be sufficient. For analysis of drug treatments in different genotypes, ANOVA followed by a posthoc. test may be needed.
For a published example of this experiment, refer to Norton et al., 2011 (J. Neurosci. 31(39):13796-13807). The setup is modified from Ninkovic and Bally-Cuif, 2006 (Methods. 39(3):262-274).