I bought 30 1inch tilapia online a couple weeks ago since I couldn't find any larger ones available nearby so I've been raising them in my fish tank until they're larger as I have an established pond. The tilapia have about doubled in size in the past 2 weeks. Does anyone have any recommendations on how big to get them before releasing into my pond ? The algae is starting to spread in my pond and id like to get the tilapia in there as soon as possible but don't want to throw them in there too early just to get eaten immediately.

Size of tilapia to stock into a pond is dependent on how big of fish the predators can eat. How big are your bass?

There's a few bass in there 16 in+. I was thinking of waiting till the tilapia were around 4inches to release them. I know a bass that size would have no problem eating them, but would they have a decent chance since my pond has a ton of cover?

Freg, the advice I've heard is to stock 20 lbs of TP per acre for algae control.

Tilapia at 4" and with 16" LMB expect 25% or more to get eaten depending on how many other food items are available to the LMB. IMO you would be better to wait another two weeks and feed tilapia all they can eat so they grow to 5"+ then release.

Or feed them behind a blocking net so they are habituated to predators before release.

Thanks for the responses. Any thoughts on whether there would be a significant difference in growth rate if I kept them in the 80 degree aquarium vs putting them in a cage in the pond which is currently around 60 degrees?

All other things being equal (water quality , space , etc.) they will grow much faster at 80 than 60.

ewest is very correct. Increase the temperature in the aquarium to 80F-84F and growth will be 3X faster than at 60F. Keep them in the aquarium until pond is 70+F. Feed them all they will eat and watch the water quality - clarity. Cloudy aquarium or tank water indicates bacteria bloom and do a water change.

Freg,

Your aquarium is at a temp that is close to optimum. It makes a difference and so yes they are going to eat more in your aquarium and hence grow more. I know you want to get them in pond ASAP but 30 fish may not control the algea ... some say the offspring does the heavy lifting. Either way, it is important that as many survive as is possible to accomplish your goal. There is no way to improve on Bill's estimate of the minimum length they need to be to be safe from predation.

As they grow it will become difficult to keep the water in the aquarium with good quality. As it warms, it might be a good idea to move them outdoors. I saw some kiddie pools at walmart last fall for $12. Something like this, a cage, or block net as earlier described by ewest could serve to house them while they grow to 5". Just don't wait too long to make the transition to more water for them.

The species is pretty important for doing a project like this. The least desirable will be those tilapia that grow fastest and take longer to sexually mature (eg Blue and Nile TP). The most desirable will be those tilapia that sexually mature earlier and at lower weights. An example would be the Mozambique TP. They will reproduce at an age of 3 months when they are only 4" or 5". So if you grew this species, they would begin reproducing shortly after release and their offspring would also reproduce.

I knew they'd grow faster at 80 than 60 degree but didn't realize it'd be that much faster. I'll try to keep them in my tank as long I can but they'll likely start getting crowded as they start approaching 4 inches( using a tank divider with other fish). Hopefully pond temps will be at least 70 degrees by then and I can transfer them into a cage. I only got 30 fish as my pond is only about an 1/8 acre and I figured that'd be around 2-3lbs which I've read is the recommend stocking rate by the time I release them.

If Niles, at 5" they will weigh just under ~3.8 and so 30 lbs/acre for the 1/8 acre BOW. Keep us posted.

I made a large cage on wheels.That rolled in and out of the pond to put them in till they got big enough to put in the pond.