Backyard Aquaponics
A place to discuss aquaponics

I am changing my system to Malaysian Prawn I have about 100 or so to start, they are in the 55 gallon fish tank now but have grown to about 1.5" already. I think after figuring out the timer issues on the outside aquaponoic system they are about ready to move out there soon and will appreciate that solar heat panel as it appears to work better then the electric heater I bought.

My question, before I build these substrates, is it better to make them horizontal like a stack of pancakes or vertical like a row of flag poles
For those of you who raise prawns which style works best and why



Just for reference The tank is about 3 foot around and about 5 foot tall , I planed to us 1/2" pvc and the orange 2" squares plastic constitution netting to build substrates
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I'll just bump this back up the post list since no ones answered yet

Not sure how many we have working with Malaysian prawns since they have a warm water requirement.

thanks

they say they grow better and faster in warmer water but since my electric heater died water has been staying cold about 72 an the prawns are doing fine

If I had to guess I'd wager horizontal given that it would be harder to get into the vertical ones?

Maybe try a bit of both and see which one gets fought over more?

Hi
I know it sounds a bit strange but Google US patents RAS commercial prawn production.
I remember reading a paper and they used an incline.
That is ; your stack of pancakes but on a slope.
So you get a deep end and a shallow end

when i search "US patents RAS commercial prawn production" I don't get anything on substrates but those stacked shallow raceways have my interest ..... that may be a future project

@goldhunter_2 - Hi, this is very interesting, can you please post some pictures on your system and how it is setup??

Regards

Must be awfully nice where you are, where I am 72 IS warm.
Seriously, I doubt that an unheated tank here would hold 70+ (21+) for more than 6-7 weeks per year, and that would be a rare year.

I too would be interested in your results. Please share. I have not seen the prawns available recently, but I have seen them in live tanks for sale at the grocers in the past, and am keeping an eye out for them again.

Titus, the sloped substrates seems almost too obvious, once you point it out. I hope to raise a few prawns or crayfish, depending on whether I heat or not, and will try this method.

Where are you located that you can get these guys? I'm dying to get hold of em!


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Yes south Florida has pretty decent weather year round we do get real cold spells now and then though but we where still able to go to the beach even the weekend after Christmas so I am hoping it makes a good climate for the prawns to grow


As far as your heat for FT, I did another post awhile back where I added two pool heater solar panels to my system and seem to work very well running the clean return water through them then to FT just make sure to add a valve or thermostat to slow the the hot water by regulating some cold and keep temp down.

I know how you feel when I decided to redo my system I looked and looked for either yellow perch and/or prawns and just couldn't find them it was very disappointing. Finally I turned to Ebay know I'd probably pay a little more for less (there are two sellers that regularly list them on there) One of the sellers happymediumaquaculturecom as here in Florida he ships but he actual hand delivered them to me since he was coming this way. It was cool to have him here giving tips and he showed me a 6 month old female and male to show size they where clear/see through and female had a sack of eggs as far as eating size the tails where about the same as a very large shrimp he told me if I wanted the 7-9" tails I have to wait until about 9-12 months old to harvest but could eat at 6 months

I bought 50 post larva (he brought little over 100) every time I see the biggest one I can't help but think about when I can eat them but I have a while to find some self restraint as I plan to keep most of them for breeders ....at least that is my plan

feed I have tried several things seller gave me a shrimp food (don't remember name) it smells like ground brine shrimp they eat it but it dissolves quick in clogs my filters, I tried duck weed to help clean water they eat allot of it then roots fall and get in filter, I had two plants in tank they eat them but now have new shouts and are leaving them alone for now. what I have settled on is wasted quail feed (Purina game bird) I sweep up form around my quail cages (they spill allot) its a 30% protein crumble mix and the prawns seem to like it and it doesn't cost me any extra and saves throwing it away, it doesn't clog my filter

filter what I found to work good so far for tiny post larva was cutting a sponge in half then hole in middle it filters water I don't have to replace store bought filter in pump and the prawns hang out on all sides of it. I will try to attach picture. when I first got the prawns they where about the size of a ink pen tip now some as as big as 1.5 to 2" long some are still smaller maybe 1/2" but sponge filter seems to work good and cheap to do

homemade sponge filter


prawns hanging out on sponge filter


random prawn pictures (sorry about bad pictures) these are mostly the smaller prawns the bigger ones didn't come out for pictures








Ok look carefully at the right corner of the bag of water that black spots are 100 or so post larva prawns that is the size of post larva I got around end of January . Mine are growing slow because of the 72 degree water is to cold the water should be around 88 degrees to grow prawns fast the guy told me. This still gives a good comparison to how they are doing for those interested

Gingerbread Man

Here is a picture of the solar pool heater panels I will be using on the outside aquaponics. one panel was probably enough two may be overkill only time will tell

Thanks very much for the pics, especially of the prawns. Unfortunately for solar, my chosen mild canadian climate rarely freezes here, but spends most of the winter grey and cloudy. (Think Seattle.) So i get little or no help from solar when I need it the most. At least my hydro is relatively cheap.