Many long-whiskered catfishes grow to be very large, including the piraiba, Brachyplatystoma filamentosum, reaching about 3 m in length. They have three pairs of barbels, with maxillary barbels that may reach the length of the fish's body. Like many other catfishes, their bodies lack scales. The adipose fin is well developed. Many species of Pimelodidae have juvenile forms that appear differently from their adult forms in color pattern, as well as body shape. Brachyplatystoma species have specialized pelagic young with greatly elongated barbels and fin filaments, and strongly ornamented pectoral spines. Other large pimelodids, such as Pseudoplatystoma, Sorubim, and Sorubimichthys, whose young inhabit vegetated, marginal waters, have distinctive cryptic coloration patterns and much enlarged caudal and pectoral fins.