The growth and survival of crawfish (Procambarus clarkii) raised in a recirculating water system at 2 stocking densities (10/m2 and 40/m2) and 3 substrate configurations (surface area, hiding place and control) is described. Crawfish grown in the control and hiding place substrates grew larger at the high density (3.9 mm and 8.9 nun, respectively) than those at the low density. At a density of 40/m2. a shift from antagonistic to passive behavior among crawfish is theorized for explaining the higher growth. Crawfish raised with the surface area substrate exhibited the best growth and survival regardless of stocking density. Further research is recommended to determine the minimum spatial requirements for crawfish growth and the maximum carrying capacity of surface area type substrates.