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Axial swimming in fish varies across a range of body forms and swimming modes. Swimming by eels, tunas, mackerels, scup, rainbow trout and bass span this range from high curvature anguilliform swimmers to rigid body thunniform swimmers. Recent work on these and other species has elucidated an impressive array of solutions to the problem of how to use the red (aerobic, slow‐twitch) muscle to power steady or sustained swimming. This review will use a comparative approach to understand the generalities of aerobic muscle function during steady swimming in fish and determine possible rules for the relationships between muscle contractile kinetics, in vivo muscle activity and power output during swimming. Beyond an exploration of the diversity in muscle activity and swimming kinematics, I suggest that analysis of the molecular basis for longitudinal variations in muscle function is needed to complement morphological and physiological research on fish muscle. This will permit both a general understanding of the integrative function of the fish myotome and, perhaps, predictive tools for muscle activity and swimming performance in fish.

The effect of obstructions in steady flow on swimming by rainbow trout Oncorhynchus mykiss was examined in a respirometry swim tunnel to test the prediction that fish interacting with obstructions require less energy to hold station. When an obstruction was present, O. mykiss altered the kinematics of swimming and the rate of oxygen consumption was significantly reduced. The fish employed both entrainment and Kármán gait swimming strategies, permitting greater locomotor efficiency.

Feeding strikes of Atlantic salmon (Salmo salar) alevins preying upon Daphnia are described using videorecording of synchronous lateral and antero-ventral views. Based on examination of characteristics such as aiming inaccuracy and capture distance, it is demonstrated that feeding behavior significantly improves during the first 2 wk after initiation of exogenous feeding. With increasing experience, young salmon tend to capture prey more quickly and with greater accuracy. First-feeding alevins use a body-ram feeding mode, relying on their swimming motion to overtake and capture prey. After 7–10 d of feeding, the fish change to a suction feeding mode that effectively uses suction generated by expansion of the orobranchial chamber to pull in prey from a distance. Also, feeding behavior of alevins raised on a commercial salmon feed lags developmentally behind the behavior offish raised on live food. This lag time is short (2–3 d), indicating that despite reports to the contrary, hatchery-raised fish do not require a Song time to learn to capture prey effectively in the wild.