4.1 Suitable Species of Fish for Culture

Unfortunately, not all fish species adapt well to tank culture, just as not all animal species adapt to being farm animals. Since fish are cold blooded, almost everything about their growth and health is influenced by temperature (see Tables 4 and 6 for details). The temperature of the culture water will partially dictate what species can or should be raised in your system. Other important factors will be how densely you intend to raise them and for what purpose or market. The rule of thumb for stocking density is 0.5 pound of fish weight per 1 gallon of water in grow out RAS. The following are considerations about what to grow for specific markets.

• What is selling in your current stores or restaurants?

• Can you address niche markets such as farmer’s markets or are there minority groups in your area that have specific preferences?

• What seasonal markets do you want to address?

• What product forms will you be willing to address?

• What is your ambient temperature for your growing period? What energy implications does that have? What is the cost?

For some producers, fish are not an important part of the overall economics of the system and are primarily “nutrient generators” for the plants. For others, selling food fish is an important profit center for the aquaponics system. Aquaponic producers may have the benefit of providing a one-stop-shop for both fish and vegetables. If that is the case, the aquaponics producer should plan ahead on what their final fish product will be. Will the fish be sold live, whole on ice, or processed? For product forms, see Figure 11. Once you are selling processed fish, there are many more issues to be considered in terms of product form and processing regulations, such as:

• Do you have access to a certified processing facility?

• Do you have current HACCP regulations for the species you intend to process?

• What does the packaging cost?

• How will processing and packaging affect your budget?

Several fish species have been successfully cultured in aquaponic systems. Overall growth parameters of these are given in Table 4. Important factors when deciding on the proper species also include availability of quality brood-stock or fingerlings, growth rate to market size, and feed cost and supply. Freshwater species are preferred, as most of the plant crops produced in aquaponics have very low tolerance of salinity. Also, hybrid striped bass (Morone chrysops x M. saxatilis), which can be raised in aquaculture recycle systems, are reported to do poorly in aquaponics due to intolerance of the high potassium levels supplemented to support plant growth (Rackocy et al. 2006), though they have been grown successfully (Diessner 2013).

Table 4: Summary of fish species suitable for aquaponics.

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