rhamphotheca:

Smooth Lumpsucker (Aptocyclus ventricosus), inflating defensively

family Cyclopteridae (the Lumpfishes).

Found in the northern Pacific Ocean. Their maximum length is 41 cm. They are both benthic (bottom dwelling) and also found higher in the water column. They are stronger swimmers than other lumpfishes, yet still not strong swimmers. The pelvic fins form a clinging disc. The body is without scales. Males guard the eggs. They feed on a variety of marine invertebrates, including jellies and ctenophores.

(photos: NOAA’s Alaska Fisheries Science Center)