Backyard Aquaponics
A place to discuss aquaponics

One other thing I read about mixed-sex Tilapia - Mixed-sex tanks have smaller fish because they start getting interested in each other instead of growing. If you have a semi-predatory fish, the mixed-sex tanks are supposed to lose some of their interest in each other, and become more interested in staying alive. Throwing a few oscars and comets in there might help keep them interested in survival instead of sex. It also lets you tell the truth about having mixed cichlids and ornamentals.

I like the split tank idea. That way you have two seperate systems on each side of the GH. If you end up with ich or some parasite, you don't lose all your fish, and some time in the future you could take one side down for cleaning, revamping, etc. You could split your raft system down the middle, and all that should be good.

If you wanted to, you could even split it 4 ways, with a tank in each of the front corners, split your sumps accordingly, etc. But splitting 2-ways would let you sex the fry (boys on the left, girls on the right [my wife tells me that girls are always right....]) You could put the fry in your sump(s) in batches, and when they are old enough to sex, pitch them in the appropriate tanks.

Sorry, just getting carried away with your setup....
You mentioned problems with too many pumps, but you can run a sump system with only one pump, and have bed fed with an overflow from the main tank (see MF's system).

Really the only reason I will take the time to sex them is because of the size thing - them having babies doesn't bother me but I don't want them to take too much time getting pan-sized.

It's good to plan for the full life cycle and several groups of fish now rather than later, once things are up and running it will be like a conveyor of fish meat!

I let them live together in the large rearing tank until I can readily identify them by flipping them upside down and checking (Yesterday I just moved my large fingerling batch from the sump to the rearing tank). After I hand seperate them, I keep the males in the rearing tank and the females in the sump tank. When the females get big enough they are eaten (or selective individuals are sold to the pet store) since they have little broodstock value lest I begin inbreeding. Then when the sump is tank is clear of females, I take my original broodstock (kept in a large aquarium off to the side) and place them in the sump along with two extra large males I now keep just for breeding (in another seperate aquarium).

When the fry appear, I remove the female and put her back in her own tank where she spits out the fry. When the fry are big enough they get swapped out with the broodstock in the sump and remain there until they are fingerlings. It takes 4 seperate tanks to do this operation.

1) Rearing tank (growout)
2) Sump tank (breeding and fingerling)
3) Broodstock tank (houses original females)
4) Nursery tank (alternates between pregnant female and broodstock males)

I suppose I could do something similar with 3 tanks and a couple of cages.

Go hard M_F

OK, 7 of the "cichlids" have moved into larger quarters -- a 72 gallon bowfront. And I bought two laundry tubs to make two more GB's for that system. I hated spending the money, but the laundry tubs are very tough and already have a drain plumbed into the bottom -- and they come with legs. And when I finish with them (move the fish and plants out to the greenhouse) I'll still be able to use them as sinks (not sure what I will use the rubbermaid tubs with drains in the bottom for....)
I'm thinking about setting up a raft system on top of my 10 gallon. Do tilapia eat plant roots? I didn't feed them much one day and they ate almost all the aquarium plants in the tank so I'm guessing they must.

Work, company, and sick kids(and reading the 100+ daily posts on the forum) have kept me from building on my greenhouse -- but I have made some major design changes so it hasn't been a total waste of time.

3 small tilapia in a 10 gallon (soon to be a raft system) and 1 tiny fish with my platties in another 10 gallon. It seemed like the big fish got all the food so that's why I segregated them.

Keep the tilapia fed and they wont eat the roots. Good idea seperating them, that way the little ones grow. It wont take long.

I haven't had much luck sexing them yet, but I haven't spent much time doing it. Should I assume that the big ones are males?

The males grow faster but since you have a mix of two batches born at different times you may have a female who is bigger simply because she's older. Here's a link to Jay's Verticle Tube System thread where I helped ID his fingerlings. http://www.backyardaquaponics.com/forum ... c&start=60

When they are young, there are subtle but distinct physical and behavioral characteristics that stand out between males and females. It can be hard for the untrained eye to spot, but just watch thier behavior.

The boys are bossy and chase the girls. The boys show off to the girls and to each other by spreading their fins and making waves at each other. Also by opening mouths wide and facing off.

hmmmm...sounds like high school.

LOL....funny how animal behavior is universal

Well, I've outsmarted my local petstores. I've been in several times and asked where they got their fish etc.... they didn't want to tell me. Yesterday I walked in and they had gotten a shipment. Name of supplier right on the box. Website and phone number prominent.

cheeky bugger

Good one :-)