Brasileirinho cavaticus is a species of freshwater isopod.

The first pair of pleopods is absent in females, and uniramous in males.

[2] The species is a troglobiont, found in a pond in a karst cave in Bahia, Brazil.

The members of the species were found to aggregate on the bottom of the pond.

The pond featured a relatively high population density, with individuals frequently bumping into each other.