Fish of different sizes

[Michael Welber]

The tilapia in my tank are growing at very different rates. After receiving them a couple of months ago when they are 3/4" big, some have now grown to 4-6 inches while others are still only an inch and a half. Any idea why this happens? Is it because some are females? The little ones hide in the corners and PVC pipe pieces that I put in the tank for them to hide in. 

[David]

I have the same problems as you with all my species but I dont mind so much because we dont eat them. In regard to tilapia my experience has been survival of the fittest where the males out compete the females for food. Also females are more interested in breeding than eating. It would be best to separate the males into a grow out tank because if there is a female in there then they would rather breed than eat as well. The same thing seems to happen with the catfish as well.

One thing about tilapia is if you leave the females mixed with males they will produce a lot of small fish and not many eating sized fish.

[George]

I don't know about tilapia but with bluegill the varieties of sizes is primarily due to genetic variation.

[RupertofOZ]

Often the variation is a reflection of your feed pattern...

 

The larger fish will usually feed ravenously at the surface... with the smaller fish waiting below... hoping for some crumbs...

 

Feed your fish until they're basically "full"... then come back about 5 minutes later... and feed a bit more again...

 

The larger fish will already be full... and the smaller fish will then get their share....

[Michael Welber]

Thanks. I'll try that.