Established m onogamous pairs of spotfish butterflyfish Chaetodon ocellatus , banded butterflyfish Chaetodon striatus , and copperbanded butterflyfish Chelmon rostratus were held in 1000 L covered fiberglass tanks each with a separate recirculating aquaculture system consisting of a trickle filter, bag filter, and UV sterilizer. Consistent lighting and temperature control were provided. Fish were fed diets consisting of frozen mysis shrimp, shaved squid, chopped krill, and Larry’s Fertility Frenzy. Each system was equipped with an upwelling egg collector designed to remove both floating and sinking eggs. Daily for up to three years, spawned eggs were collected, volumetrically quantified, and percent fertilization was determined and recorded.
Chaetodon ocellatus spawned 203 times in 805 days with a total of 2,298,864 unfertilized and 80 fertilized eggs for a mean of 11,325 eggs/spawn. On 71 days when there was a spawn , a spawn occurred the next day. Chaetodon striatus spawned 172 times in 795 days with a total of 1,049,193 unfertilized eggs and 433 fertilized eggs for a mean of 6,100 eggs/spawn . On 26 days when there was a spawn , a spawn occurred the next day. Chelmon rostratus spawned 126 times in 851 days with a total of 1,714,357 unfert ilized and 86,171 fertilized eggs. There were 19 spawns with fertilized eggs with a mean of 4,535 fertilized eggs per spawn. There were 126 spawns with unfertilized eggs with a mean of 13,606 unfertilized eggs. On 56 days when there was a spawn , a spawn occurred the next day, and on 10 more days a spawn occurred two days later. Further research is justified to identify causes of unfertilized eggs. This is the first reported spawning data for these three species of butterflyfishes held in captivity.