January 8, 2015
Tilapia is one of the most commonly raised fish species in aquaponics systems, but it is not universally desirable among consumers. Why is it that tilapia is such a common choice, and why are we raising them at the CLF Aquaponics Project?
- Tilapia are hardy. Really hardy. In the aquaculture industry they have a reputation for being very difficult to kill, especially compared to more finicky species such as trout. They can survive wider ranges in pH, temperature, and ammonia than many other fish species, and they quickly adapt to varying conditions.
This made them a great choice for us and many other aquaponics growers who are typically new to practicing aquaculture.
- Tilapia are fast growing and efficient at converting food into body mass. Their feed conversion ratio, or the ratio of mass of food added to the mass of fish produced, ranges from about 1.6-1.8:1, far less than a carnivorous fish species like salmon (and farmed shrimp) and a mere fraction of the feed conversion ratio for other sources of protein, like beef which can be as much as 20 to 1. This means we can minimize our feed inputs to the system.
- Tilapia eat plants…and insects, algae, worms, fish and, well, a bit of everything. This omnivorous diet means they can adapt well to an entirely plant-based fish food, allowing the farmer to potentially avoid using fish feed made from large amounts of fish-meal, a product typically made from wild-caught, pelagic fish, such as mackerel and sardines. Unfortunately, plant-based fish foods are not yet commonplace and price competitive on the commercial market. However, alternative fish foods are a growing area of research as the aquaculture industry expands and the price of fishmeal rises. Many aquaponics farmers have even experimented with growing their own fish food by raising worms, soldier fly larvae or duckweed. We hope to begin trying to grow some of our own fish feed soon.
- Tilapia are popular. Tilapia are one of the top five fish species consumed in the U.S., meaning that they are easily recognizable for consumers.
If farmed properly, tilapia’s low-feed conversion ratio and omnivorous diet make them an environmentally friendly fish species to eat. However, tilapia do have a few disadvantages. Because they are hardy and can eat a diversity of food, tilapia are not always raised in healthy conditions or fed a high quality feed. They have fewer omega-3 fatty acids than other fish species, such as sardines, mackerel or salmon, and in many parts of the world tilapia are an invasive species. Moreover, cheap production of tilapia in Asia has driven down prices, making it difficult for farmers to receive fair payment for their fish. While tilapia are a great choice for beginning aquaculturists, other fish species that can be raised in aquaponics include catfish, perch, bluegill or even ornamental koi.