Comment

Comment by Sheri Schmeckpeper on March 28, 2012 at 10:56pm

Dave, I believe it depends on the type of prawns/shrimp. There's a type of fresh water shrimp that's being raised here with tilapia. Well, in the sump usually. Not directly with the fish. They grow very large.

The midge larvae, also called bloodworms, are GREAT food. For fish, I mean. If you have them growing in your system, you're blessed, in spite of the swarming. :)

Comment by Jon Parr on March 28, 2012 at 10:22pm

SW, is it possible that your "mosquitos" are midge larva? I had midges swarming in my heated greenhouse through the winter, and thought they were Mosquitos, and couldn't figure out why I never got bit. So I looked them up. Midge adults look exactly like Mosquitos, but midge larva are little red worms, that thrive in both tanks and growbeds, feasting on organic matter and bioslime. They are a bit annoying because they swarm when stirred, but are harmless and tilapia eat both larva and adults.

Comment by SW on March 28, 2012 at 9:49pm

Water flow through my 2 breeding tanks where I had the mosquito problem is a bit over 100 gallons per hour. Both have a couple of 8" air stones and the water is very healthy.  I think the real culprits were the eddy areas around the pots and pvc which allowed quite areas for the mosquito to lay their eggs in the gravel.

I wish my fish would have taken care of the problem!  I was vacuuming up 200 - 300 mosquito's per day from the porch ceiling.

No gravel - no problem!

Comment by Dave Lindstedt on March 28, 2012 at 8:30pm

Christian, I think the real question is, what is your objective.  If it is raising tilapia, I think the pools should work well.  If your goal is aquaponics farming, I don't think that large a pools would be practical.

Comment by Dave Lindstedt on March 28, 2012 at 8:08pm

My daughter in law's brother raises both tilapia and prawn in the Philippines.  He has a 6 acre lake they service with a row boat.  He exports over 10,000 tilapia each year to Japan.  From what I understand PH requirements between tilapia nd prawn vary widely, so they are not raised together.

Comment by TCLynx on March 28, 2012 at 7:47pm

some people have done it successfully Christian, however, some pool liners contain chemicals meant to kill algae and bacterial growth and can become toxic to fish.  I'm not sure how to tell which pools contain the toxic chemicals and which do not.

Comment by Christian De La Nuez on March 28, 2012 at 7:44pm

Quick question.. Has anyone in here ever used the above ground pools as grow out tanks? Thinking about getting 2-6000+ gallon above ground pools. All input is appreciated.

Comment by Sheri Schmeckpeper on March 28, 2012 at 7:41pm

Very interesting observations, Dave. I'm glad they've been reproducing well! I've heard both directions about tilapia eating their young. I've always pulled them except in two instances. One time about 20 were left with their mother and over half of them grew faster than the ones we pulled. The others we suspect became hors d'ovres. Another time we left babies too long with mother and the numbers began declining after her nurturing phase ended. So while I've never witnessed the action, I've believed they would. It's interesting that the larger fingerlings were so aggressive about it.

Comment by TCLynx on March 28, 2012 at 7:23pm

If you don't have enough tanks to keep fry/fingerlings separated by size, you can look into setting up multiple cages in a bigger tank to keep the fingerlings segregated by size.

Beware though, if you get too many fish, they will stunt and now grow out large.

Comment by Dave Lindstedt on March 28, 2012 at 7:18pm

This past month has been a real learning experience for me. I have two primary tanks with mature fish. A self built 330 gallon tank with 20 to 25 fish and a reinforced 275 polly tank with 3 to 5 fish all survivors from my July 2011 original fish purchase. I started with 220 fish.  Last Nov. I had a major fish kill.  So getting these guy to reproduce has been a major priority.

About a month ago I spotted about a dozen brand new fry in my 330 gallon tank. Within 3 day I nolonger saw them.  I made up my mid to try and find them and seperate them.  So I scrubbed out my 40 gallon aquarium and filled it up.

With some effort I managed to net 2 fingerlings (about 3/4 inch) and 15 to 20 fry (under 1/2 inch) and put them in the aquarium.  About this time I spotted a major ball of fry near the surface of my polly tank.  Over the next 2 or 3 days I managed to net about 50  of them and moved them into the aquarium.

But now I nolonger saw any of the smaller fry from my big tank.  Guess what within 3 or 4 days I could not find any of the more than 50 fry I put in from my polly tank.  Now many had suggested the little guys were hidding. But I started to think differently.

So I netted about another dozen fry from the polly tank and put them into the aquairum.  Instantly the two bigger fingerlings went nuts, attacking the the new little guys. With considerable  effort I manged to net these two (now over 1 inch) fingerlings and moved them into a 2nd polly tank. 

For the last week I have been netting 50 to 60 of these fry from my main polly tank and moving them into the aquairium.  These guys are very "social".  They stick together and congregate in a ball eating the algee from the sides of the aquairum.  They like the light. I have a aluminum dome covered 75 watt light I clip to the side of the tank and turn on and they congregate under the light bulb.

Conclusion is larger fingerlings see small fry as a threat and a food source.  You MUST seperate them by size.  Because of the sparce density of fish in the polly tank (I think only 1 male) breeding was prolifice many offspring.  I did not get this type of action in my big tank.  While breeding in the big tank had taken place, I tend to think some of the males were eating the eggs and any surviving fingerlings were eating the little fry.

When the little guys in my aquarium grow out to over an inch I will gradually move them into my 2nd polly tank with the two fingerlings I removed from the aquarium.   I still have about 50 to 75 of the little guys swimming around with their parents in my first polly tank.  I will try and remove them before they become large enough to pose a threat to any new batch of fry.

I will also look to try and net 3 to 5 of my mature fish in the large tank (hopefully 1 a male)  into another tank with a view to more breeding.  Never can have too much fish.  

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