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I am trying to choose which fish to stock in a commercial aquaponics system in North Alabama / Southern Middle Tennessee, where the average annual temperature is 63 degrees F. I like to eat Tilapia, but the heating bill would eat ME alive. The obvious choice is catfish, but I just don't like the taste. There is likely a pretty good market for the fish, but competition may well keep the cost low, since catfish is so common (haven't checked yet). Browsing the fingerlings for sale on the Dunn's Farm website, I came across the description for Grass Carp, which sounds like they grow really fast, and are good to eat (at least the chinese think so according to Wikipedia). Anyone had experience with these, or even heard of them before? Would I feed them the same commercial feed used for catfish? (The grass carp eat mostly vegetation in the wild - hence the name.)

 

I read of a system in a permaculture book where algae is grown in one section of a fish tank with a screen which keeps out the fish, but allows algae to pass through to feed the fish. I think it would be worth experimenting with a similar idea with fast growing underwater plants as feed for vegetable-eating fish.

 

Any other suggestions for mild temperature loving (65 to 80 degrees), fast growing marketable fish?

I am also getting the impression that there is very little profit in the fish side of commercial aquaponics, and that I should plan on the profit coming from the produce. If that is really the case, then I really just need good fertilizer factories for fish. I would like to prove this idea wroing, however....

 

TimW

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As far as tilapia go, yes blues are relatively "cool tolerant" but I would definitely not try raising them where the average water temperature is going to be 65 F.

Cool tolerant means they survive in water below 60 F.  And I've had Blues survive nights with water down to 53 F but if the water gets cooler than that on them you may have immune system problems where the fish will tend to get sick and die later even if they survived the water going below 53 overnight.
  And when I had some Blues that I couldn't catch and remove from one tank and that tank later dropped to 48 F, the fish were dead.

I actually experienced far faster growth from my channel catfish than from my mixed gender blue tilapia in an outdoor system in inland central Florida.  Now if you got fingerlings  of blue tilapia in the spring once the water is 70 F and you fend them really high protein feed and keep the water quality really good you might get 1/3rd lb tilapia you could eat after about 8 months but then if the water cools off they are going to be lucky to make it to between 1/2-1lb over the rest of the year without heating.  With the channel catfish I could get fingerlings in spring and if they were advanced fingerlings I could have a fish that was 1 lb in that same 8-10 months while feeding them lower protein feed than the tilapia needed and the channel catfish are still eating well when the water is below 70 F (I didn't actually  completely quit feeding the catfish until the water was almost down to 55 F) and after a year with catfish I usually have fish between 2-6 lb.  Catfish can also survive water down to about freezing as long as the temperature swings are gradual and you don't let the water freeze over.

For fast growing big fish to eat in a system that does get really warm in summer, I recommend channel catfish.

If you just need fish that can survive some cold and handle really warm and they don't need to grow real fast or you have some problem with catfish, then go bluegill.

If the water never gets really warm (much above 70 F) and really spends most of its time between 55-65 F then look into trout for a fast growing fish.

Have you looked into Yellow Perch?   Great tasting fish in short supply.  Similar to Tilapia in temp. needs but will tolerate much lower temps than Tilapia.  I'm having trouble finding stock in my area. 

yikes!  sorry, but yellow perch aren't anything like tilapia as far as temp requirements.. they spaw in cold water (50's)

and won't handle high temps very well..they are considered a "cool water" fish, and do best at around 70-74f

 

yellow perch is my favorite tasting fish, you can grow (most) to eating size within a year, if you start with 3-4" fingerlings

Possibly because we have so many good fish here.  It'll be interesting to see if carp make my top 20.  My grandson and I came home the past couple of days with flounder, red drum and spotted seatrout, all very good fish.

Vlad Jovanovic said:

I believe many people (mostly just Americans it seems) have been conditioned to 'automatically' respond to carp in such a negative light.

I just started a backyard aquaponic system in Shanghai, China. I currently have 5 grown Crucian carps which I used to kick off the cycle and just added 10 Tilapia fingerling. Well, I started with 10 grown Crucian carps but family took advantage of availability of fresh fishes right in the backyard. 

However, being in Shanghai, the Tilapia isn't going to live through the winter when the outdoor temp will be around 40F. I have been doing researches on the fishes to grow and found out about the 4 main fishes account for 80% of the annual fish production in China: Grass Carp, Black Carp, Silver Carp and Bighead Carp. 

There are quite a few interesting ways to keep these fishes and many suggest to mix them. Grass carp can be feed with grasses and the poo can facilitate the growth of algae and plankton which will be eaten by Bighead carps. All these sounds very interesting but I wonder how the algae will affect the nutrients in the water for the plants. 

I just want to say hi to others who are interested in testing carps as AP fishes. I am leading toward trying the mix of grass carp and bighead carp. I will post result. 

63 degrees F

this temperatures suitable for trout and sturgeon

Well, we have good tasting fish here in Europe too. We just count carp among them :)

George said:

Possibly because we have so many good fish here.  It'll be interesting to see if carp make my top 20.  My grandson and I came home the past couple of days with flounder, red drum and spotted seatrout, all very good fish.

Vlad Jovanovic said:

I believe many people (mostly just Americans it seems) have been conditioned to 'automatically' respond to carp in such a negative light.

I have had good luck with Rainbow trout. They like the cooler water, at my place the water is 20c/68f all year. It takes about 9 months to start to harvest. Right now I buy the food for them.

Yeah, no kidding.  Great article about the blind taste test.  Coincidentally, I was on Kentucky Lake last week fishing for Crappie (appetizing name) and we saw Asian Carp cruising around.  They are considered by and large to be a worse than worthless invader but maybe people will start eating them eventually, or at least harvest them for some useful purpose.  There are plenty of them and they get very large.  Seriously, I will try them but I was not equipped to catch them on that trip. People in that area shoot them with bows but I believe they are just wasted afterwards.

Vlad Jovanovic said:

Hi David, good to meet you here. I consult to fish farmers in Beijing and can attest that it is common practice here to mix species  In fact, I believe people in Asia have a much better, more holistic approach to farming than many modern, western cultures. We not only produce fish in our ponds but manage to harvest a variety of symbiotic creatures like fresh water prawns, muscles and snails.

David Li said:

I just started a backyard aquaponic system in Shanghai, China. I currently have 5 grown Crucian carps which I used to kick off the cycle and just added 10 Tilapia fingerling. Well, I started with 10 grown Crucian carps but family took advantage of availability of fresh fishes right in the backyard. 

However, being in Shanghai, the Tilapia isn't going to live through the winter when the outdoor temp will be around 40F. I have been doing researches on the fishes to grow and found out about the 4 main fishes account for 80% of the annual fish production in China: Grass Carp, Black Carp, Silver Carp and Bighead Carp. 

There are quite a few interesting ways to keep these fishes and many suggest to mix them. Grass carp can be feed with grasses and the poo can facilitate the growth of algae and plankton which will be eaten by Bighead carps. All these sounds very interesting but I wonder how the algae will affect the nutrients in the water for the plants. 

I just want to say hi to others who are interested in testing carps as AP fishes. I am leading toward trying the mix of grass carp and bighead carp. I will post result. 

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