The male discharges seminal fluid into the water as the eggs are deposited. Larvae at hatch are approximately 30 mm long. When they reach 100-130 mm, at about 18 months of age, they lose their external gills. Diet includes crayfish, earthworms, and various insects. They are nocturnal.
Hellbenders are highly vulnerable to pollution and siltation of their rivers and streams.
From highway construction to urban runoff, channelization and damming of rivers for reservoirs, man has effected hellbender populations through-out its range. The Hellbenders role in river and stream ecology is important to the very people who endanger it. Hellbenders keep crayfish populations in check, allowing more and bigger game fish to develop. They also prey on weak and diseased fish, thus controlling disease spread and allowing the strong and healthy to grow. Where they thrive, so do everything that needs clean, oxygen-rich water.