Please refer to this page, which has a comprehensive introduction to aquaponics.
Typically, aquaponics enthusiasts use Tilapia because they’re incredibly hardy, grow quickly, and can be harvested as a food source! Tilapia require slightly higher temperatures, so a small tank heater may be a nice addition to increase their metabolism and help them grow faster. If you’re not interested in harvesting your fish, goldfish and koi are great alternatives. People have also experimented with crayfish and freshwater shrimp.