Skipjack tuna, 39–50 cm fork length, were studied during their first month in captivity in tanks 7.3 m in diameter and 1.1 m deep. Water temperatures were 23.3° to 25.7° C. Passage of food through the alimentary canal was estimated from 54 fish that were fed as many thawed smelt as they would eat. At intervals from 2 min to 24 hrs later pairs of fish were removed and the wet and dry weights of the stomach and intestinal contents were measured. The fish ate the equivalent of about 8.6 per cent of the body weight. About 10 per cent of the original quantity eaten passed from the stomach each hour during the first 8 hrs and the stomach was essentially empty within 12 hrs after a meal. The content of the intestine reached a maximum after about 5 hrs. The intestine was empty within 14 hrs, but some of the food material moved into the digestive gland and apparently re‐entered the intestine later. Blood glucose averaged 132 mg/100 ml blood from 0.5 to 7 hrs after a meal but 81 mg/100 ml blood 10 to 24 hrs after a meal. Food consumption was examined in relation to the quantity of food material in the stomach in three other experiments: (1) Skipjack tuna fed at intervals after a meal, began feeding before their stomachs emptied and even ate more than had already passed through from the stomach. For example, 4 hrs after a meal they ate 75 per cent of the amount eaten at the earlier meal, whereas only 50 per cent of the earlier meal had emptied from the stomach. (2) Skipjack tuna were fed at 15‐min intervals throughout the day. Although a period of intense feeding occurred between 0630 and 0830 hrs, the fish did not fill their stomachs to capacity the first or even the second or third time they were offered food, but filled their stomachs slowly over the 2‐hr period. Maximum capacity of the stomach was about 7 per cent of the fishˈs weight, but during the whole day they ate an equivalent of 15 per cent of their body weight. Skipjack tuna ate more food and digested it more rapidly than other fishes for which data are published. (3) The responses to food were observed as the fish ate and their stomachs filled. The proportion of food particles attacked decreased after the stomach was half filled and the percentage of food particles to which the fish responded began to decrease after the stomach was about 80 per cent full. The results are discussed in relation to the effects of satiation of the food drive on pole‐and‐line fishing for skipjack tuna near Hawaii, and the relation between feeding motivation and the quantity of food in the stomach.