Background & Objective: Vitamins are complex organic substances that are needed by the body in small amounts, usually cannot be synthesized by the body but are important in metabolic processes one of which is vitamin B. Vitamin B consists of vitamins B1, B2, B3, B6, B9 and B12. Eel is one of the fish that has a high nutrient content, one of which is vitamin B. This study aims to determine the levels of vitamin B (B1, B2, B3, B6, B9 and B12) in Eel fish (Anguilla marmorata (Q.) Gaimard) on Elver phase from Lake Poso. Material and Methods: Determination of vitamin B1, B2, B3, B6 and B9 using HPLC (High Performance Liquid Chromatography), and vitamin B12 using LC-MS (Liquid Chromatography-Mass Spectrometry) . Results: The levels of vitamin B2, B3 and B12is 0.133 mg/100g, 1.895 mg/100g, and 0.017mg/100g, whereas in vitamin B1, B6 and B9 is not detected. Conclusion: Eel fish (Anguilla marmorata (Q.) Gaimard) on Elver phase from Lake Poso can be used as a source of vitamins B2, B3 and B12.