Macrourus berglax shrimps, amphipods, polychaete worms, bivalve molluscs, isopods, brittle stars, other echinoderms and comb jellies. The roughhead grenadier is a slow growing fish. The females mature at an age of about 14 years and a length of while males reach maturity at a length of . The potential fecundity of the female is 17,000 to 56,000 eggs. The eggs are laid in batches and spawning takes place at any time of year, with a peak in late winter and early spring. The roughhead grenadier is landed as a by-catch when fishing for Greenland halibut ("Reinhardtius hippoglossoides") and Atlantic halibut ("Hippoglossus hippoglossus").
Jellynose fish Jellynose fish The jellynose fishes or tadpole fishes are the small order Ateleopodiformes. This group of ray-finned fish is monotypic, containing a single family Ateleopodidae. It has about a dozen species in four genera, but these enigmatic fishes are in need of taxonomic revision. The scientific name means ""Ateleopus"-shaped", from "Ateleopus" (the type genus) + the standard fish order suffix "-formes". It ultimately derives from Ancient Greek "atelís" (ἆτελής, "imperfect") + "pús" (πούς, "foot") + Latin "forma" ("external form"), the Greek part in reference to the reduced pectoral and ventral fins of the jellynoses. Jellynoses are deep-water, bottom-dwelling, marine fishes.