Richard bray

Rainbow Trout

• Harvest weight: 16oz-20oz
• Time to harvest: 9-13 months
• Feed: aquatic insects, small fish, manufactured trout feed

Trout are an easy, fast-growing species that are a perfect companion for cool-season crops. Trout must maintain a cool water temperature or else they become stressed, making them susceptible to disease anc throwing off your system.
It is much easier to heat water than it is to cool it, which is why trout is generally only used in mild, cooler climates. Trout perform best in a constant-flow system that is over 250 gallons. They are not suited for smaller systems, and they become stressed very quickly in still water
Trout are the most marketable fish that can be grown in an aquaponic system, so they work very well for growers who want to make a profit from a few focused leafy-green crops, and a modest fish harvest.
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The biggest drawback to trout is the temperature and size requirements, but this does make them perfect for large-scale leafy green production in a somewhat controlled climate.
Goldfish/Koi

• Harvest weight: N/A
• Time to harvest: N/A
• Feed: aquatic insects, algae, aquatic plants, manufactured food

Goldfish and koi are more versatile fish as far as the plants they can support, but the obvious disadvantage is that you can’t eat them. This makes them perfect for growers who don't eat meat, or have no interest in harvesting fish from the tank.
Another advantage is that goldfish live 5-10 years, and koi can live up to 30 years in a healthy environment. This means that once a system is stocked and ready to plant, you won’t need to spend money restocking fish.
One interesting phenomenon of goldfish and koi is that they excrete a chemical into the water that will limit their growth. This is why goldfish stay small in aquariums, when they have the capacity to grow over a foot long in the wild. When water is being circulated through the system, but only a fraction of it is held in the fish tank, the fish may think they have more water to use as a living space than they actually have access to, which can result in oversized fish that become crowded.
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