Figure 1.

Example zebrafish tank provided from stills of video data collected during (A) baseline and (B) corresponding object presentation. Two tanks were set-up with this orientation and four tanks were set-up in the reverse direction (slope on the right and deep-end/object presentation area on the left). The baseline period (A) was defined as at least 1 h before a novel object was introduced into the tank. The concentric outlines around the object in panel (B) are overlain on both videos to indicate the areas within approximately two zebrafish body-lengths from the object and four zebrafish body-lengths from the object. Fish presence in the inner area (two body-lengths) was used for the analyses. Each object-tank combination had its own outline to control for differences in object size and shape so that interest scores could be calculated as the number of fish in the inner area beyond the number observed during baseline: interest score = fish in inner area_{object presentation} – fish in inner area_baseline.