Feeding experiments were conducted using nine species of damselfish collected at Lizard Island (14°40′S; 145°27′E) in the northern GBR in June 2015. Fish were placed individually in 32-L flow-through aquaria and starved for 24 h prior to feeding trials. Fish (n = 6–9 per species and treatment level) were randomly assigned to one of the six feeding treatments using varying proportions (0, 20, 40, 60, 80 and 100%) of eggs of Acanthaster sp. versus squid-mantle flesh. The fate of each food pellet of each treatment was recorded as: (1) accepted—the fish immediately retained the pellet; (2) mouthed and accepted—the fish retained the pellet after spitting it out one or more times; (3) mouthed and rejected—the fish rejected the pellet after capturing and spitting it out several times; (4) rejected—the fish rejected the pellet after capturing and spitting it out only once; or (5) untouched—the fish visually inspected the pellet and rejected it without mouthing.
The full methodology is available in the publication shown in the Related Publications link below.