ABSTRACT The survival of several fish species in captivity depends on their adaptation to the environmental conditions and the biological characteristics. The objective of the study was to evaluate the influence of different light intensity levels in growth, behavior and skin pigmentation in juvenile of Lophiosilurus alexandri. Fishes were exposed to the following luminosities: 0, 218, 278, and 459 lux. The experiment was conducted for 75 days, in a water recirculation system with controlled temperatures and aeration. Catfish juvenile were distributed in 35 L aquariums, at the density of 0.28 ind L-1. In order to evaluate fish growth, weight, standard- total length, weight gain, food consumption, food conversion, biomass, specific growth rate and survival were measured twice times a month. Also, swimming behavior, skin pigmentation and plasma cortisol levels were evaluated. Light influences L. alexandri feed consumption, food conversion, behavior and plasma cortisol levels. Environments with low light are recommended for the L. alexandri growth.