Bellwood studies the ecology, biogeography and evolution of marine fishes, and in 2016 was elected to the Australian Academy of Science.

[1] He worked on North Sea inshore fishing trawlers and trained in taxonomy at the Natural History Museum in London, under zoologist Geoffrey Boxshall.

[1] Bellwood completed his PhD research at James Cook University in Townsville, Australia, where he studied parrotfishes from 1981 to 1985.

[4][1] Bellwood's research interests are wide-ranging, and his work spans the "systematics, evolution, biogeography, biology and ecology of reef fishes from both tropical and temperate seas.

"[1] Bellwood currently teaches ‘Reef fish evolution and ecology’ and ‘Marine biogeography’ at James Cook University.