 The sicklefin lemon shark , or sharptooth lemon shark ( Negaprion acutidens ) , is a species of requiem shark belonging to the family Carcharhinidae , widely distributed in the tropical waters of the Indo @-@ Pacific . It is closely related to the better @-@ known lemon shark ( N. brevirostris ) of the Americas ; the two species are almost identical in appearance , both being stout @-@ bodied sharks with broad heads , two dorsal fins of nearly equal size , and a plain yellow @-@ tinged coloration . As its common name suggests , the sicklefin lemon shark differs from its American counterpart in having more falcate ( sickle @-@ shaped ) fins . This large species grows up to 3 @.@ 8 m ( 12 ft ) long . It generally inhabits water less than 92 m ( 302 ft ) deep in a variety of habitats , from mangrove estuaries to coral reefs . 
