The objective of the study was to describe the total postlarval length of Trichomycterus rivulatus Valenciennes, 1846 (suche) under controlled conditions. A total of 887 postlarvae of T. rivalatus after 25 days post-hatching was used as biological material. Water quality (temperature, dissolved oxygen and pH) was controlled. Before each feeding, siphoning was done to remove food debris and 90% of the water volume was replaced in all treatments. Growth (total length) was measured with a millimeter ruler (precision ± 0.01) at the beginning and end of the experimental phase. Survival for each experimental treatment before live feed supply was: T2 = 99.66% > T1 = 98.97% > T3 = 97.63%. At 21 days the postlarvae showed an average total length of 21.6 ± 0.51 mm, while at 45 days the total length was 30.53 ± 0.52 mm. A statistical difference was found between the total length at 21 and ...