Head very broad (width 28-31% SL, 96-109% HL); body dark brown marbled or with narrow vermiculations, and low and anteriorly truncate first dorsal fin. Distinguished from highly similar species Cottus hispaniolensis by the following characters: pelvic fins hyaline or with faint brown marks; low and anteriorly truncate first dorsal fin; last dorsal-fin ray connected to body by a membrane along 1/3-2/3 of its length; last anal-fin ray not connected to body by a membrane; and fewer lateral line pores (31-32+1). Differs also from other Cottus in Atlantic drainages by the following characters: caudal peduncle stout (length 14-18% SL, depth 8-10% SL and 1.5-2.1 times in its length); no prickling in adults, a few prickles under pectoral fin in juveniles; eye diameter 20-25% of HL; interorbital distance 1.1-1.4 times in eye diameter; no membrane between last pelvic-fin ray and body; membranes between pelvic-fin rays wider distally (Ref. 55856).