Backyard Aquaponics
A place to discuss aquaponics

How long does it take to raise fingerlings to harvest size for these fish?

Trout?

Tilapia?

Catfish?

And how long does it take to raise a batch of freshwater prawns?

We're trying to get a handle on what the best option for our climate and our food preferences.

it's all going to depend on lots of factors..
tilapia will grow really fast if the water is in the mid to high 80's,, from fry to plate in about 6 months.. cooler water will take longer
trout on the other hand like much colder water, and lots of oxygen.. from fry to plate in 6-9 months if water is in the 50's
for the catfish, i've seen a few people on here grow them out quite large over a couple of years (read TCLynx's stuff)

The catfish in my pond went from fry to over a pound in 6 months.

According to my research, for North Carolina climat, the Tilapia is a better choice. If you get them in April, by October they will be big enough to harvest them.
That is the reason I went with Tilapia. Remember to apply for a permit if you decide to go with Tilapia.

Here is a pic of when I put the catfish in my pond.



And here is a pic 6 months later with no supplemental feed.

And here is tilapia fry



And almost 2 months later.

How well they take to feed has some to do with it too. I procured my tilapia from the wild, so they took a while to go onto pellets. I'm sure once they have fry, those fry will grow out much faster as they will only have known feed.

Ok. That i very usefull guys. How do i mesure how much fish can i putt in one tank...of 1500 gallons. Trout, carp, catfish

Base it upon your ability to filter their waste, not how much water you have. How are you planning to clean the water for the fish? The ammonia created by the fish needs to be removed from the water or it will become toxic for the fish and they will die. For this, aquaponics uses a biological filter (media beds or MBBF or ???) which uses microbes to convert the deadly Ammonia to slightly less deadly, but still toxic Nitrites and more microbes to convert the Nitrates to less toxic (at normal concentrations) Nitrates, then the plants use the Nitrates as food to leave the water much cleaner and less toxic for the fish. A simple rule of thumb for amount of media bed to handle your bioload (amount of fish) is 25 liters of wet media per 500g of fish. Start conservative on your fish load and with experience you can increase the amount of fish you keep alive (with better filtration, extra oxygen, etc.) Driving slow is much easier for beginners than racing a Formula 1.




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Sam