It is native to the Indo-Pacific from the Red Sea and East Africa, to the Pitcairn Islands, southern Japan, and Australia, and can also be found in some parts of the Philippines.

D. trimaculatus and D. auripinnis are parapatric (their ranges overlap in the Northern Cook Islands), but the four species are otherwise all allopatric.

[3] Mitochondrial genome analysis found that D. trimaculatus itself can be split into three populations: Indian Ocean, southern French Polynesia, and West-Central Pacific.

D. auripinnis has been found to clade with the West-Central Pacific population of D. trimaculatus, which raises some doubts as to the former's validity.

[4] Its grey to black body has two lateral white spots and one between the eyes like domino hence the name; the threespot dascyllus grows up to 13 cm (5.1 in) in length.