The ornamental fish trade has considerable potential for damaging reef environments. Nearly 120 species are currently harvested in the Brazilian trade and little attention has been paid to the effects of the accidental catch of these species. Records of ornamental fish by-catch and the susceptibility and resilience of species from the major Brazilian families in the aquarium trade were examined to test a method and determine the sustainability of these catches. Each species was assessed based on two groups of criteria: (1) relative vulnerability to capture; and (2) population resilience to mortality due to fishing efforts. Each species was also ranked (1–3) for criteria regarding ecology, biology, catchability, numbers of individuals exported by aquarium companies and mortality index. These criteria were then weighted and each species rank in the two groups of criteria was plotted. Nineteen species from 10 families were recorded. The species least likely to have sustainable catch rates included Holacanthus tricolor, H. ciliaris, Chaetodon striatus and Pomacanthus paru. This approach is a useful alternative for management efforts and the assessment of catch sustainability in newly developed multi-species fisheries with limited available data, which occur in areas of high species richness such as reefs.