Enzyme extracts from two fish species, bluefish and sheephead, were subjected to hydrostatic pressure treatments ranging between 1000-3000 atm for Various durations and the residual activities of cathepsin C, collagenase, chymotrypsin- and trypsin-like enzymes compared with those of their bovine counterparts. The fish enzymes were generally more susceptible to hydrostatic pressure inactivation than their mammalian counterparts. Fresh fish muscle tissues were also subjected to similar pressures and the color and textural parameters determined. The color generally became lighter presenting a cooked appearance to the fresh fish flesh with increasing pressure as well as holding time. There was general toughening/hardening of the tissue when 1000 atm of pressure was applied. The upper limit for maintaining or enhancing tissue hardness was the application of 2000 atm for 10 min. Beyond this point, the tissue generally becomes softer with pressure and holding time. Copyright (C) 1996 Published by Elsevier Science Ltd on behalf of the Canadian Institute of Food Science and Technology