The redfin bully (Gobiomorphus huttoni) is a species of freshwater sleeper goby endemic to New Zealand. Being amphidromous, it spends part of its life cycle at sea. Males have distinctive bright red patterns and stripes on their fins. Adults grow to an average of 80–100 mm (3.1–3.9 in) total length, with a maximum of 120 mm (4.7 in).