Edit Butis butis

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Name

Scientific name

Butis butis

Described by

Authority Hamilton, Year 1822, Bracketed

Family

Butidae

Common names

Crazy Fish

Photograph credits

All 2 credited

Summary

The crazy fish, Butis butis, is a flathead gudgeon of coastal and brackish waters across the Indo-Pacific, from eastern Africa to Fiji. The…

Size and aquarium

Maximum size

120mm, standard length

Aquarium size

Minimum length 75 cm, Minimum depth 30 cm

Water

Water conditions

Temperature 22–27°C, pH 7–8.5

Hardness

10–20dGH

Conductivity

Not recorded

Behaviour

Temperament

Territorial

Community suitability

Not for a community

Where it lives

Countries, regions, rivers and lakes

Australia, Bangladesh, Brunei, Cambodia, China, Fiji, Hong Kong, India, Japan, Kenya, Macau, Madagascar, Malaysia, Mauritius, Mozambique, Myanmar, New Caledonia, Palau, Papua New Guinea, Philippines, Seychelles, Singapore, Somalia, Sri Lanka, Taiwan, Tanzania, Thailand, Vietnam, Mascarene Islands, Mekong

Writing

Etymology

Not written yet

Distribution

Type locality is 'Ganges River, below Calcutta, India', but this species is very widely-distributed throughout much of the Indo-Pacific with records existing f…

Habitat

Generally inhabits coastal, brackish environments such as estuaries, lagoons, and mangroves but also known to penetrate tidal freshwater rivers to an extent. I…

Aquarium size

A single specimen can be maintained in an aquarium with base dimensions of 75 ∗ 30 cm or equivalent but larger quarters would be required by a group or if you …

Maintenance

Best-maintained in brackish water although the precise specific gravity is unimportant provided it does not exceed that of seawater (1.025). Try to find out th…

Water conditions

Not written yet

Diet

This species is an ambush predator feeing mostly on smaller fishes, worms, and crustaceans in nature. In the aquarium it readily accept prepared alternatives s…

Behaviour and compatibility

Territorial and may react aggressively towards related or similarly-shaped species, while smaller fishes and invertebrates will be preyed upon. The most suitab…

Sexual dimorphism

Unknown.

Reproduction

Not thought to have occurred in aquaria.

Notes

B. butis is the most commonly-traded member of the genus and is known by a number of vernacular names with other English examples including 'crocodile fish', '…

B. butis is the most commonly-traded member of the genus and is known by a number of vernacular names with other English examples including 'crocodile fish', 'crimson-tipped flathead gudgeon', 'crimson-tipped flathead-sleeper', 'crimson-tipped gudgeon', 'duckbill sleeper', 'flat-headed gudgeon', 'pointed-head gudgeon', 'bony-headed gudgeon', and 'upside-down sleeper'.

According to Rainboth (1996) it's diagnosable via the following combination: teeth in outer row enlarged; upper jaw extending to anterior portion of eye; 20-25 predorsal scales; body shallow, its depth fitting 5-6 times in its standard length; interorbital space and cheek below eye scaled.

Butis spp. are largely nocturnal ambush predators with cryptic patterning to help them blend in with their surroundings. They can also lighten and darken their body colouration to an extent, have a habit of aligning themselves with solid surfaces whether horizontal, vertical, or inverted, and often swim in an upside-down position.

The genus is usually included in the family Eleotridae of which members are often referred to collectively as 'sleepers', 'gudgeons' or 'bullies'. The grouping is included in the suborder Gobioidei and species can be separated from the related families Gobiidae and Gobionellidae (commonly referred to as 'gobies') by lacking fused pelvic fins, never possessing an inferior mouth, possessing separate spinous and rayed dorsal fins, and presence of six (rather than five) branchiostegal rays, the latter feature being shared with other gobioid families Rhyacichthyidae and Odontobutidae.

The reproductive cycle of most eleotrids features a marine stage although the majority live in freshwater as adults and some are entirely restricted to such habitats. They tend to be bulkier and possess heavier scaling on the body than most other gobioids.

The family is traditionally split into two nominal subfamilies with Butis included within the Butinae alongside the genera Bostrychus, Incara, Kribia, Milyeringa (sometimes included in the family Odontobutidae), Ophiocara, Oxyeleotris, Prionobutis, and Typhleotris, and all other eleotrids contained in the Eleotrinae assemblage.

Neither subfamily is considered monophyletic, however, and a series of morphological and molecular phylogenetic studies have been carried out, though thus far no definitive conclusions have been reached.

This lack of monophyly has led to the two subfamiles being raised to full family level as Eleotridae and Butidae, respectively, with Thacker (2009) demonstrating that Butidae is sister to a clade containing Gobiidae and Gobionellidae, with Eleotridae sister to that clade of three families based on the results of her molecular analysis of the suborder Gobioidei.

This hypothesis was rejected by Agorreta and Rüber (2012)[5], however, who concluded that this molecular phylogenetic hypothesis is 'unstable' and fails to definitively rule out a number of alternative theories, thus it cannot be used as a basis for changes in classification.

Eleotridae is certainly not monophyletic though since Eleotrinae does not share a most recent common ancestor with Butinae, and it seems clear that additional study is required to resolve the higher-level taxonomy of the grouping.

At any rate Butis spp. can be separated from other eleotrids by the following combination of characters: scales on body ctenoid, at least posteriorly; scales moderate to large, typically fewer than 100 in the lateral series; preopercle without spine; predorsal scales in fewer than 30 rows; bony irregular ridge or row of spiny serrations above eye and on top of snout (spines may be indistinct); lower jaw distinctly anteriormost, chin protruding; head without fleshy knobs or barbels on chin; distinct black spot on pectoral-fin base or on bases of pectoral-fin rays; marine to estuarine life history.

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References

8 on this profile

Name

Scientific name

Described by

Family

Common names

Photograph credits

Summary

Size and aquarium

Maximum size

Aquarium size

Water

Water conditions

Hardness

Conductivity

Behaviour

Temperament

Social needs

Community suitability

Where it lives

Countries, regions, rivers and lakes

Writing

Etymology

Distribution

Habitat

Aquarium size

Maintenance

Water conditions

Diet

Behaviour and compatibility

Sexual dimorphism

Reproduction

Notes

References

References