The odour from coral bleaching is masking the smell of predators to small reef fish, a Queensland study has found.

A research team of scientists from James Cook University and Sweden's Uppsala University spent two months on a field study at the northern end of the Great Barrier Reef last year to determine whether coral bleaching affected small reef fishes' ability to detect their predators.

Damselfish, considered the "model" fish for other reef species, were used in the study, which found degraded coral reefs muddied their ability to work out who predators were.

The findings were published in Proceedings of the Royal Society B.