Chemical composition and fatty acid profile were studied in larvae and adult Trans-Andean shovelnose catfish muscle. The chemical composition in dry matter of the larvae and the food they consumed were: moisture, 89.2%, 91.8%; protein, 79.8%, 70.6%; ethereal extract, 7.8% 7.2%; and ash, 12.7% and 14.5%, respectively. In adult muscle there were no significant differences between sexes in the percentages of moisture, protein, ethereal extract, and ash. Similarly, there was no statistical difference between sexes for monounsaturated fatty acids and polyunsaturated fatty acids. A significant difference between the sexes was found in the fatty acid profile which showed a predominance of saturated fatty acids. This study demonstrated that there is a great similarity in the chemical composition of the species. The percentage of protein and variation in ethereal extract and ash content was dependent upon the composition of its food. These results provide basic information for formulating adequate nutritional diets to meet the requirements of Neotropical fish.