All fish / Butidae

Crazy Fish

Butis butis

Also known as crazy fish, duckbill sleeper, upside-down sleeper, bony-snouted gudgeon, butis gudgeon, crazy goby, ปลาบู่หัวแบน, ikan belodok, ヤナギハゼ, ikan beloso, 锯脊塘鳢, 丁氏塘鳢

A slim sleeper goby with a flat, pointed head and a mottled brown body flecked with red dots. It often hangs at odd angles or upside down beside roots and rocks, and that strange habit is where the trade name comes from. Keepers like it for its behaviour and its character as an ambush predator.

Care at a glance

Care level

Moderate

Temperament

Semi

Adult size

12 cm

Temperature

22 to 28 °C

pH

7 to 8.5

Smallest tank

100 litres

Keep as

Singly or a small group in a roomy tank with plenty of cover

Diet

Carnivore: live and frozen foods such as bloodworm, brine shrimp, mysis, small shrimp and small fish

Swims

Bottom of the tank

Lifespan

5 to 8 years

Water

Brackish

Wild range

Indo-West Pacific coasts, from East Africa and India through Southeast Asia to northern Australia and Fiji

Breeding

It lays adhesive eggs on hard surfaces and the male guards them, but the larvae are thought to need brackish or salt water to develop. Breeding in home aquariums is very rarely reported.

Good to know

It is sold as a freshwater fish, but it lives in estuaries and mangroves and does best long term in brackish water. It will eat any fish or shrimp small enough to fit in its large mouth.