Tank for aquaculture or fish farming in these systems can be of many shapes and size like rectangular, circular, oval, etc. Mostly circular and oval tanks are preferred because they are easier to clean and facilitate easy water circulation when compared to rectangular tanks. Rectangular tanks are generally used on inclined areas. The size of a fish rearing tank may range from 500 to 500k gallons capacity and this depends on the factors like the type of fish, stock rate, water requirement, and quality. The tank should be built such that it is compatible with the other components of the systems. The materials required to built the tank can be metal, wood, glass, rubber, concrete, or plastic. Any material which is non-toxic and doesn’t corrode can be used constructing the tank. The inner surface of tank should be clean and smooth. Each and every material used for this purpose has its own advantages and disadvantages. The inclination of the fish tank can help to drain easier but has little or no affect of self-cleaning ability.
Most modern tanks are being constructed with outlets that have optimal waste removal capacity and are fitted with suitable mesh screens. These outlets should also make removal of dead fish easy. Some tanks are also fitted with sensors to detect the water level, oxygen content, temperature, etc. so that they can be controlled automatically. Tanks should also have diffusers for a sufficient supply of oxygen.
Other than circular and rectangular tank, there is one more variety called the raceway tank which is a blend of circular and rectangular shapes. These tanks have a wall in the center to facilitate circulation.
