Logo for N.C. Cooperative Extension N.C. Cooperative Extension Homepage

Species Selection & Stocking for Cage Culture

Species Selection & Stocking for Cage Culture

Species Selection

Species selection and stocking is mostly based on availability and water temperature. Common species that have been cultured in cages with their temperature and stocking requirements can be found in Table 1.

TABLE 1. Species, optimum temperature range, temperature extremes (high and low), stocking time and temperature, and stocking rates

Species Temp Range
Temp Extremes
Stocking Time
(month, temp °F)
Stocking Rate
(#/cubic ft.)
Rainbow Trout 55-65 <45, >70 Sept-Nov, 60-65 4-12
Channel catfish 80-85 <45, >95 May-July, 60-70 5-9
Bluegill 80-85 <45, >95 May-July, 60-70 5-9
Tilapia 80-90 <55 June-July, 70 5-12


Stocking number is based on cage volume. Stocking at lower densities the fish will get bigger in a shorter time than when stocking at higher densities. In cage culture, fish are stocked between 6″ to 8″ in order to get a 1-lb fish at end of the growing season. Stocking at densities lower than recommended may result in aggressive behavior. It is also important to stock fish at approximately the same size. Bigger fish have a tendency to dominate smaller fish. This will reduce the growth rate of the smaller fish.

Handling fish is stressful to the fish. The best time for stocking is when the water temperature is cool. This will lessen stress-related disease and mortality. It is also important to temper the fish to the existing water body temperature. If water temperature differs by more than 5 °F or 2 pH units, the water should be slowly exchanged between the pond and the hauling container. This usually means exchanging half the container water with 1/2 of the pond water. Periodically check the temperature. If after 15 to 30 minutes, the temperatures still differ more than 5 °F, repeat the procedure by exchanging 1/2 the container water with 1/2 the pond water. Repeat until the pond temperature and container temperature are approximately the same. If the fish are in a bag, you can place the bag in the receiving pond water to allow the temperatures to equilibrate.

Examine the fish that are being stocked. Fish should be healthy. Healthy fish have no sores, blotches, or frayed fins. A healthy fish will avoid being captured and will dart or swim rapidly when approached.

NCCE Aquaculture Home Page

By: Molly Sandfoss, Area Specialized Agent – Aquaculture
Last Updated: August, 2003

Page Last Updated: 1 decade ago
Was the information on this page helpful? Yes check No close