To showcase their would-be nursery, male jawfish court females by swimming in a series of swoops, arching their backs and flaring their fins.

This scary creature looks like something from another planet - it's a jawfish spotted off the US coast.

I first encountered a male jawfish with a mouth full of eggs in 2010 while diving in Wakatobi National Park, in Indonesia, while doing independent undergraduate research.

Of the eight such families, three consist solely of paternal mouthbrooders: jawfish, cardinalfish, and sea catfish.