Butis is a genus of sleeper gobies in the family Eleotridae.

Their resting behavior has resulted in the vernacular name "sleeper gobies", which invites confusion with the related family Eleotridae.

Sleeper gobies are members of the Eleotridae fish family, found predominantly in the tropical Indo-Pacific.

Eleotridae - Known commonly as gudgeons, many species in the family Eleotridae are also called sleeper gobies.

Valenciennea - hover gobies, "sleeper gobies"

Although goby-like in many ways, sleeper gobies lack the pelvic fin sucker, and that, together with other morphological differences, is used to distinguish the two families.

Sleeper gobies are a closely related family (Eleotridae) that lack the fused pelvic fin sucker typical of most gobies, but are otherwise very similar in size, shape, and ecology.

However, their territoriality and because even the smallest species are fundamentally carnivorous and need living food to thrive make them not easy to keep (particularly compared to the related sleeper gobies family Eleotridae).

There are some predatory sleeper gobies that get much bigger, such as the marbled sleeper goby, Oxyeleotris marmorata, a freshwater species from Southeast Asia that can grow to 2 ft (60 cm) long.

However, most are much smaller, such as the fresh and brackish water species from Australia like Hypseleotris spp., known locally as gudgeons (not to be confused with the Eurasian freshwater cyprinid Gobio gobio, also known as the gudgeon and after which the Australian sleeper gobies were likely named).

Kimberleyeleotris is a genus of fish in the Eleotridae family.

They are classified under the family Eleotridae.

Oxyeleotris expatria is a freshwater sleeper goby from the family Eleotridae.

In Australia, gudgeons from the family Eleotridae are widespread and are popular for aquariums.

The family of Eleotridae are often referred to as sleepers; this is because these fish usually lie still on the bottom as if they were asleep.

Sleeper gobies are members of the Eleotridae fish family, found predominantly in the tropical Indo-Pacific.

The Barnett River gudgeon (Hypseleotris kimberleyensis) is a species of fish in the Eleotridae family.

Gudgeon is the common name for a number of small freshwater fish of the families Cyprinidae, Eleotridae or Ptereleotridae.

Unlike gobies, Eleotridae gudgeons have paired ventral fins rather than a fused ventral fin.

Eleotridae - Known commonly as gudgeons, many species in the family Eleotridae are also called sleeper gobies.

Eleotris sandwicensis, commonly known as the Sandwich Island Sleeper or Hawaiian Sleeper, is a species of fish in the Eleotridae family.

Graham's gudgeon, Grahamichthys radiata, is a New Zealand sleeper of the family Eleotridae, the only member of the genus Grahamichthys.

The genus has traditionally been placed in Eleotridae, but it is of uncertain placement within Gobioidei and some have tentatively placed it in its own family Milyeringidae.

Oxyeleotris marmorata, the marbled sleeper or marbled gudgeon, or Soon Hock in Cantonese, is a widely distributed species of freshwater fish in the family Eleotridae.

However, their territoriality and because even the smallest species are fundamentally carnivorous and need living food to thrive make them not easy to keep (particularly compared to the related sleeper gobies family Eleotridae).

This is a manifestation of the phenomenon known as convergent evolution, and has been observed in Characidae, Cyprinidae, Eleotridae, Gobiidae, Poeciliidae, Siluriformes, Synbranchidae and various other families.

Fish in the Eleotridae family are often primary predators in streams and ocean islands in and around areas such as Hawaii and New Zealand where larger predators are absent.

It is widely believed that the Gobiidae and Eleotridae share a common ancestor, and they are both placed in the suborder Gobioidei, along with a few other small families containing goby-like fishes.

The Peacock gudgeon, also known as Peacock goby, Tateurndina ocellicauda is a tropical freshwater fish belonging to the genus Tateurndina of the Eleotridae (Sleepers) family, Eleotrinae subfamily.

The Flinders Ranges mogurnda or Flinders Ranges purple spotted gudgeon, Mogurnda clivicola, also known as the Barcoo, or Bulloo mogurnda, is a Central Australian gudgeon of the Eleotridae family.

Alfred Stauch, ichthyologist (Bothus, Chiloglanis, Chiloglanis benuensis, Chiloglanis voltae, Dagetichthys lakdoensis, Dalophis, Dasyatis, Eleotridae, Niger stingray, Phractura, Spinycheek sleepers, Zaireichthys, Zaireichthys camerunensis)