Like concrete, fiberglass tanks can be molded into a variety of shapes and sizes. The potential size of tanks used for fish culture is limited only by expense and engineering capabilities. Most tanks used in fish culture are circular or oval with the water inlet causing a rotary circulation. The inlet is generally above the water level in the tank to provide aeration as it enters. The water usually exits through a standpipe or bottom drain in the center of the tank.
Circular tanks have several advantages over other tank shapes and raceways.
Water velocities tend to be higher, feed distribution is better, they are easier to maintain, require a lower flow rate, and generally cost less to construct and install. Culture Net pen culture consists of raising fish in box shaped nets suspended in the water column. To date, most of the culture of this type in the northeast has been for salmon in shallow bays along the coast. However, recent advances in designs of floating pens have allowed the culture of trout and other species in inland waters and man made lagoons. There are two types commonly used in fish culture.