Experimental test tank schematic: arrangement of fish and apparatus during and between trials.

<p>Plan view of test tank before and between trials (A) and during trials (B): focal fish (F), companion fish (C) contained in transparent plastic cylinder during trials, two areas where live <i>Daphnia</i> sp. were delivered during trials (D), speaker (S) behind opaque partition (P) during trials, mesh partitions (M) separated fish between trials. Fish in separate sections of the tank between trials with mesh partitions allowing visual, acoustic and olfactory contact.