Upon hatching, the 3 mm fry are carried downstream to the sea; several months later, they return as 15–20 mm juveniles, and live the rest of their lives in fresh water. Redfin bullies seem obliged to spend their first few months at sea, because no landlocked populations have been found. Juveniles have the best climbing ability of the "Gobiomorphus" species, but are mostly found in lowland waterways. They reach sexual maturity in their second year and have an average lifespan around 3–4 years.