Backyard Aquaponics
A place to discuss aquaponics

If I grow my tilapia to 1 and 1.5 pounds what amount of meat can I expect? It there a percentage of body weight?

Headed, scaled and gutted, about 50%. Filleted, about 33%.

Ok, so if I want 360 pounds of meat in a year I need 1100-1200 pounds of fish or perhaps 800 fish.. Wow, thats a lot of fish!

How many gallons of water to a pound of fish? For a well stocked system.

250grams is a good serve

1200 lbs -> 3600 gallons of water -> 7200 gallons of grow bed

That's if your raising them all at the same time of course. If you recycle the same volume for different fish then it's less.

250g is a half pound. I personally would eat half of that for my meal. Of course, I must have a dainty and lady-like appetite.

If you are practiced, 4gal growbed to 2 gal fishtank to 1 pound fish (4:2:1). However, I should note that even though I have long aquarium experience, I'm running at 5:5:1, and don't think I will really go much denser. Growbeds (ammonia-processing capacity) are the more limiting factor rather than gallons of water, and I'm feeling that for the work I want to put into it, 5:1 (growbeds to fish) is a better ratio for me than 4:1.

With practice, you should be able to grow out tilapia to the size you want in 9-10 months. Using multiple tanks or multiple sizes of fish in one tank means that you don't have to be able to handle 800 fish all at once.

So at a ratio of 4:2:1 would I need to inject oxygen?

My 480 gallon tank would only hold ~100 fish at 5:5:1 I can see thoughs ratio "5:5:1" would be a lot safer from any mishaps.

Am I planning for disaster at the thought of stocking at 200 one # fish?

Next year, when I go large scale, I want to do all my growing at once because they will be out side. I do not want to add the expense of heating all that water during the winter. I plan on keeping 3 100 gallon tanks and 300 gallons of grow bed in their own small heated building. These 3 tanks will be used to keep the breeders and fingerlings in their own tanks. The idea is, to breed the little fish earl spring and move them outside until early winter then shut down for the winter.

Of course Im also looking into These gas pond heaters. $380 seems cheap enough, but again Im not shure I really want to heat a thousand gallons of water when its freezing.

The reason I want 360 pounds of fish per year is because my family eats a pound of meat every day. Also, I can trade, pound for pound, fish with a family farm for chicken and beef.

Insulated tanks and cold water species = easy care

We choose tilapia because of the flavor. We really don't like a strong fishy taste. Also, tilapia area easy to breed.

Can you tell me what cold water fish are easy to breed and kosher(fins and scales[that can be scraped off])? The family I will be trading with eat like the jewish people and I think there are some health benefits to eathing that way also.

Not off the top of my head. Worth researching though.

edit: a list of kosher fish: Kosher fish

Bluegill caught me eye. Good for eating, indigenous to most of the US.

Bkaus,
If you want to put 200 1lb fish in your 480gal tank, you need a minimum of 800gal growbeds AND good fishkeeping experience. My system is limited by the growbeds, not the fishtank. Technically, I could run the same growbeds and fish with a 75gal fishtank, but I am more comfortable with a larger volume of water--it makes the system more stable.

No one here injects oxygen, although some of us run an airstone (aka "bubbler") if we think we are pushing the limits or see signs of distress. We all try to ensure splashing and good air exchange, regardless. For your first batch of fish, I would seriously recommend going with 800gal growbeds, but fewer than 200 fish if you can--just to get practice and learn the limits of your system and you yourself. For your next batch, try 800-1000gal growbeds, and 200 fish.

Dan,
The native fish are going to be harder to breed in a tank environment. I looked into yellow perch at one point, and they require a certain sequence/range in temperature and light. You could look in to purchasing batches of fingerlings each spring from a local hatchery. Or perhaps your trading partners have a good Jewish recipe for carp (gefelte fish?). I believe carp would be easier to breed yourself.

gefilte fish is usually a whitefish/pike mix. And tasty!

Plan for big growbed volume at the start, it's tempting but wrongheaded to size for the big fish tank but short on the grow beds.

So I need at lest 2 more GB ~270gal to get the 800gal But that's 4 more tons of gravel to wash I have off Thanksgiving week "make more GB's"