The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Butis koilomatodon
Butis koilomatodon
(mud sleeper)
Marine Fishes

Copyright Info
Butis koilomatodon (Bleeker, 1849)

Common name: mud sleeper

Taxonomy: available through www.itis.govITIS logo

Identification: The mud sleeper has a moderately flattened head with a pale beige to brown body (Macieira et al. 2012).  It is distinguished from similar species by four to seven regular bands on the body and a serrated snout with a row of short spines (Macieira et al. 2012).  There is a large black spot on the pectoral fin base (Marceniuk et al. 2017).

Size: 6.9 cm SL (Macieira et al. 2012)

Native Range: Indo-Pacific Ocean from Africa to China (Dawson 1973).

Interactive maps: Point Distribution Maps

Nonindigenous Occurrences: Brazil: Panaquatira Beach, Araçá Bay, São Sebastião Channel (Contente et al. 2016, Lamas et al. 2016); the coastal towns of Curuçá, Soledade, Mosqueiro, Mucuri, Conceiçáo da Barra, Piraque-açu, and Rio Escuro (Macieira et al. 2012); tidal pools on island of Maiandeua, beaches of Fortalezinha and Macarico (Soares et al. 2012); Rio Caeté estuary (Marceniuk et al. 2017); Maranhão state, São Luis, Araçagy Beach (Guimarães et al. 2017)

Panama: Miraflores Locks, Panama Canal (Dawson 1973)

Venezuela: Caño Pedernales and Caño Venado in the delta of the Orinoco River (Lasso-Alcala et al. 2005)

Ecology: This fish exhibits mostly sedentary lifestyle in lower reaches of rivers, estuaries, tide pools, and mangrove habitat where they feed on crustaceans, mollusks, and small fishes (Macieira et al. 2012, Soares et al. 2012).  The mud sleeper is able to tolerate wide ranges of temperature (26-37 C) and salinity (3.8-37.3 ppt; Contente et al. 2016).

Means of Introduction: Probably ship-mediated, via ballast based on its presence in ports (Bonfim et al. 2017, Dawson 1973, Macieira et al. 2012).

Status: Most likely it is established (at least in Brazil), collections included small juveniles and adults (Macieira et al. 2012).

References: (click for full references)

Bonfim M., A.P.B. Martins, G.K.F.C. Carvalho, N.M. Piorski, and J.L.S. Nunes. 2017. Non-native mud sleeper Butis koilomatodon (Bleeker, 1849)(Perciformes: Eleotridae) in Eastern Amazon Coastal region: an additional occurrence for the Brazilian coast and urgency for ecological assessment. BioInvasions Records 6(2): 111-117.

Contente, R.F., M.R.Brenha-Nunes, C.C. Siliprandi, R.A. Lamas, and V.R.M. Conversani. 2016. A new record of the non-native fish species Butis koilomatodon (Bleeker 1849) (Teleostei: Eleotridae) for southeastern Brazil. Biotemas 29(2): 113-118.

Dawson, C.E. 1973. Occurrence of an exotic eleotrid fish in Panamá with discussion of probable origin and mode of introduction. Copeia 1973 (1): 141-144.

Lamas, R.A., C.L.D.B. Rossi-Wongtschowski, and R.F. Contente. 2016. Checklist of fish fauna of the Araçá Bay, São Sebastião Channel, northern coast of São Paulo, Brazil. Checklist 12(6): 2004.

Lasso-Alcala, O.M., A. Lasso, F. Pezold, and M.L. Smith. 2005. The mud sleeper Butis koilomatodon (Pisces: Eleotridae): first record from the Western Central Atlantic. Rev. Biol. Trop. 53(1-2): 211.

Macieira, R.M., T. Giarrizzo, J.L. Gasparini, and I. Sazima. 2012. Geographic expansion of the invasive mud sleeper Butis koilomatodon (Perciformes: Eleotridae) in the western Atlantic Ocean. Journal of Fish Biology 81: 308-313.

Marceniuk, A.P., R.A. Caires, M.M. Rotundo, R.A.K.de Alcântara, and W.B. Wosiacki. 2017. The ichthyofauna (Teleostei) of the Rio Caeté estuary, northeast Pará, Brazil, with a species identification key from northern Brazilian coast. Pan-American Journal of Aquatic Sciences 12(1): 31-79.

Soares, B.E., T.O.B. Ruffeil, and L.F.A. Montag. 2012. Occurrence of the non-native sleeper Butis koilomatodon (Bleeker, 1849) (Perciformes: Eleotridae) in the Amazon coastal zone, Brazil. BioInvasion Records 1(2): 95-99.

Other Resources:

Author: Schofield, P.J., and M.E. Brown

Revision Date: 8/13/2020

Peer Review Date: 7/10/2017

Citation Information:
Schofield, P.J., and M.E. Brown, 2021, Butis koilomatodon (Bleeker, 1849): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=3170, Revision Date: 8/13/2020, Peer Review Date: 7/10/2017, Access Date: 9/24/2021

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2021]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [9/24/2021].

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