Increased prey capture in Octopus tetricus paralarvae through enhanced visual contrast

The domestication of octopus for large-scale aquaculture remains unfeasible due to high paralarval mortality, largely attributed to inadequate nutrition from single-item diets such as regular Artemia . As active visual predators from hatch, paralarvae rely on visual cues to capture prey, making prey visibility critical for survival. This study investigated the visual preferences of Octopus tetricus paralarvae for live Artemia enriched to produce different visual contrasts: microalgae yielded dark Artemia , food colouring produced white Artemia , and no enrichment yielded pale Artemia . These different coloured prey were presented in tanks with either black or white backgrounds for the paralarvae to make a choice between the prey offered. Of 154 paralarvae observed in black tanks, 90 (58%) made successful captures compared to 90 of 241 (37%) in white tanks. Across all 180 successful captures, white Artemia in black tanks were most frequently captured (31%), followed by dark Artemia in white tanks (24%). Median capture time for white and pale Artemia in black tanks was 73 s, at least 58% faster than any other colour–background combination. These findings show that visual contrast between prey and background significantly improves feeding success in cultured octopus paralarvae. Incorporating prey colours that contrast with rearing tank backgrounds could enhance capture efficiency and potentially improve survival in culture.