Crazy Fish Butis 5cm

Crazy Fish (Butis butis)

The Crazy Fish (Butis butis), also known as the Duckbill Sleeper Goby, is one of the most unusual and fascinating species available in the aquarium hobby. Its cryptic appearance, ambush predatory behaviour, and ability to blend into its surroundings make it a standout for aquarists looking for something truly different.

This species displays a mottled pattern of browns, greys, and earthy tones that allows it to camouflage perfectly against substrates and décor. Its elongated body and wide, flattened head give it a unique profile, while its eyes are positioned for ambush hunting. These fish are largely sedentary, often sitting motionless before quickly striking at prey. Their behaviour alone makes them incredibly interesting to observe.

Sexing is difficult, and breeding in captivity is rarely achieved. In the wild, they are ambush predators that rely on stealth rather than speed.

Tank Recommendations for your Crazy Fish

A minimum aquarium size of 80–100 litres is recommended, depending on size. A sandy or fine substrate with driftwood and hiding spots is ideal. Lower lighting helps them feel secure and display natural behaviour.

Suitable Tank Buddies

These fish are predatory, and tank mates must be chosen carefully.

Usually Compatible

Similar-sized robust fish that are too large to be eaten.

Sometimes Compatible

Other bottom-dwelling species in larger aquariums.

Rarely Compatible

Small fish, shrimp, or nano species, as they may be viewed as prey.

Feeding your Crazy Fish

These fish are carnivorous ambush predators and prefer meaty foods. The ideal diet would be frozen foods such as bloodworms, small fish, or prawns, with some individuals accepting pellets over time. Faster-moving tank mates can easily outcompete this species, so care should be taken when feeding.