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sleeper definition
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sleeper
any of the marine and freshwater fishes of the family Eleotridae of the suborder Gobioidei (order Perciformes). Sleepers, found in warm and tropical regions, are so named because most species habitually lie quietly on the bottom. They are elongated fishes with two dorsal fins and are distinguished from most other gobies in having their pelvic fins separate, rather than joined to form a weak, rounded suction cup
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