They excavate nests under rocks and defend against other males. Females enter the nest and lay a string of up to 400 marble sized eggs. The male covers the eggs in seminal fluid and remains to guard them from predators. Additional females may subsequently enter the nest site and lay eggs with the male fertilizing them as well. Depending on water temperature, the eggs may develop in as little eight weeks.
Hatchlings resemble the parents except they have external gills.
The gills are resorbed toward the end of the second year when the salamander is about 12 cm long. Sexual maturity is attained by the end of the third or fourth year, when the salamander is about 34 cm long. Cryptobranchids are almost always found in relatively shallow areas of cool, fast-moving, clear mountain streams where shelter is available in the form of large rocks or snags. They spend much of their time hidden and emerge at night to forage for food. When moving about on the streambed they are very cryptic.