2.1 Fish Culture

Fish tanks for aquaponics come in a wide range of shapes, sizes, and materials, with selection being largely based on culture species. The majority of large systems use round tanks that either have a flat- or cone-bottom. Use of tangential flow will prevent dead zones when used in round tanks (Figure 2). Cone-bottom tanks allow solids to concentrate at the bottom (in the cone) and be easily flushed from the system. Flat-bottom tanks are more widely available, but solids removal requires additional steps to ensure proper removal of organic material dispersed across the bottom of the tank.

Square tanks may also require additional cleaning as solids or debris can settle in corners (Somerville et al. 2014). Sizing for fish culture tanks follow RAS principles, with a 3:1 width to height ratio being ideal for proper water movement and flow. Fish tanks are generally the highest point of the system and water flows via gravity to the solids filtration component.

Commercial-grade tanks are commonly made from strong, UV-stable materials like high-density polyethylene (HDPE) plastic or fiberglass. On a smaller scale or in areas with limited resources, intermediate bulk containers (IBC) or lined cement troughs may be utilized. Food-grade and UV resistant materials are necessary as many repurposed tanks may have held chemicals or hazardous materials, making them unsuitable fish intended for consumption.

Source: Janelle Hager, Leigh Ann Bright, Josh Dusci, James Tidwell. 2021. Kentucky State University. Aquaponics Production Manual: A Practical Handbook for Growers.