Backyard Aquaponics
A place to discuss aquaponics

I have completely designed my system and im using a 3000L tank

I'm going to start with 100 silver perch fingerlings, but i dont want to have to harvest about 100 fish at around the same time so im looking into incorporating a 1000L fingerling tank to raise up the baby fish on their own a bit so they can grow big enough to be safe from being eating by bigger fish, that way i can have silvers of different sizes in the same fish tank and put in however many new little fellas every 4 months or so and they will be big enough they cant be eaten, while at the same time harvest the bigger ones more regularly in smaller numbers as they reach plate size

So the question is..

How big does a silver perch have to be for it to not be eaten by a large silver perch (around 500 grams)

Silvers are predominantly herbivorous, and are not known to be canabalistic.

One problem you may run into is the littlies not getting enough food cos the biggies come and are more aggressive in the procurement of pellets.

+1 for above, and only 10% of the fish will be big at the same time.

10% bolters, 80% middle range, 10% runts.

oh i see thats good then

so i could put in a mesh divider to seperate a quarter of the tank out which the bigger fish couldnt get through and the babies could

and when i feed them, throw feed into the mesh quarter first to attract all the babies into that area, then throw out my other feed in the rest of the tank to the other bigger fish

That would be an interesting technique for grading fish if you can get it to work...
Problem is little ones will stay on the food side, then grow big. so you'd have to get them back over the other side somehow.

yeah..

well ive compmletely designed my system now and im pretty proud of it so not its just time to go make it
but i thought if i was going to need a fingerling tank (which my uncle has said i could use a 1000L fiberglass tank of his) then i should set it up at the same time

but i see your point there, but everytime i am going to put in the new fingerlings into the tank, i would be harvesting my big ones, and if there were any fish that had grown too big inside the small area, i could just net them and put them into the bigger area...?

maybe if you could remove the screen, then put it in at one end, and use it as a net, so all fish are on one side, then only the small fish could get over?
I don't know... it's difficult to design complex things whilst trying to keep them robust and simple.

we've had fingerling and big perch in together, and feed two grades of food

ok well as long as they wont be eaten then that makes things alot easier
thanks for the advice guys

i wont worry about the fingerling tank now it sounds like its not even needed

now i can just start getting my system going the way i planned it, ive drawn up my design and i will put it on my own system thread in the next day or two

and if anyone sees any areas for improvement id be happy to hear it

anyway, cheers
mav

Maverick the mesh divider thingy actually sounds like a good idea! I've seen it used similar in an actual aquarium so that fry didn't get eaten. Same principle, just on a bigger scale! But from all accounts I've heard the silver perch don't tend to eat each other, BONUS!

Hi Mav,

I have a CHIFT PIST system with a sump tank and had 30 nice sized SP (400 grams) in the main tank.

I purchased a bag of 100 SP fingerlings and put them into the sump tank and left them there until they were eating 4mm pellets - this took around 3 months. All the fish were then moved into the main tank and I had no problems with feeding or growing out the fish.

At feeding time, the larger fish would grab the first lot of pellets and dive to the bottom of the tank - the smaller ones were lined up ready for the next spoonful - with SP, they just eat their fill and tend to not over eat -the pecking order is quickly worked out and all get to eat as long as sufficient pellets are avail.

There is no need to worry about cannibalism or the runts missing out too much with SP

meant to add - by removing the plate sized fish, the next in line are more than willing to show their muscle at feed time - not realising that they are now in line for future BBQ's

Thanks for the information that all sounds good, except i see a problem

How do i stop the little fellas from getting sucked into the pump in the sump tank?

A grille tends to work well
Most pumps have a guard that will prevent fish scale confetti