Introduction to Aquaponics
Fish
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Fish Selection and Profiles
- It is usually recommend using Gold fish or carp if you are starting off in Aquaponics as they are the most robust fish and produce large quantities of ammonia which is ideal for Aquaponics. As you become more comfortable with ‘water quality’ and the balancing of fish and plants you should move into edible fish.
- A lot of places in the world people use the fish Tilapia (oreochromis niloticus) due to their fast growth rate (6 months) and quantity of meat per fish. However, under 18°C they will not eat and under 12°C they will die. Tilapia are more expensive to keep in the UK climate as their tanks would have to be heated.
- In the UK and Ireland it is most common to grow cold water fish such as trout (Oncorhynchus mykiss), bream (Abramis brama) or simple goldfish (Carassius auratus).
Carp & Gold Fish
- Common carp is a popular pond fish. Common carp are used as a pond fish because they are very disease resistant, tolerate wide temperature and pH range, and will accept different food types. They are ideal for starting with.
- pH range: 6.0 – 9
- Temperature range: 1° C- 32° C
- Optimum temperature: 12° C- 24° C
- DO level: 4 mg/l and a maximum of 10 mg/l
- Growth time: 0.6 Kg in just over 6 months in ideal conditions.
Tilapia
- Tilapia is a hardy fish and highly recommended for use in Aquaponics. Tilapia is primarily cultured because of its high adaptability. Tilapia has a high growth rate and frequent spawning tendencies. It is thus an ideal fish for Aquaponics because of its rapid growth, large size, and because it tastes great. It only takes about 9 months for Tilapia to grow to a harvestable size, roughly 1.5 pounds, and this hardy fish can adapt to most any condition with the exception of water temperature. Tilapia need warm water – at least 75 degrees Fahrenheit as it is a tropical fish and so it requires a heated tank which can be expensive.
- Tilapia eat duckweed, ground-up salad greens from the greenhouse, worms, and Tilapia love to eat algae from the side of the tank.
- pH range: 7-8
- Temperature range: 12° C – 30° C (under 18° C they will cease eating)
- Optimum temperature: 26° C
- DO levels: 3- 10 mg/l (can survive as low as 1 but not advised)
- Growth time: Under ideal conditions can grow 1.13 Kg in 6 months
Catfish
- Most catfish are bottom-feeders, meaning they swim and eat at the bottom of the tank. There are many varieties of catfish and the specific requirements should be investigated further. They are negatively buoyant, which means that they will usually sink rather than float due to a reduced gas bladder and a heavy, bony head. Catfish have high heat tolerances just like tilapia, but they can also thrive in the cold.
- pH range: 5.0 – 7.0 (can live in 5.0 -9.0)
- Temperature range: 4° C – 35° C
- Optimum Temperature: 23° C – 30° C (under 10° C they will cease eating)
- DO level: Minimum of 1 mg/l but 4 mg/l is ideal for growth
- Growth time: Harvested at 0.5 Kg in just over 6 months in ideal conditions.
Rainbow Trout
- Rainbow trout has many characteristics that make it suitable for Aquaponics: it is easy to farm, it is quite resistant to diseases. However, this fish can be more sensitive to environmental factors than some of the other factors and so should only be grown by an experienced fish keeper.
- pH: 7- 8
- Temperature range: 5 -24° C
- Optimum temperature: 23
- DO levels: not less than 5.5 mg/l,
- Growth Time: roughly 12 months