Introducing New Tilapia to an Existing System

[Mike Bavas]

We have about a 150 gallon tank with only 5 tilapia that are growing quickly.  We were set back with a slow leak but now that we have another tank, we plan to order about 20-25 fry.  Will the five who have been settled in the tank for 2-3 months be aggressive to the newcomers?  Should we introduce them slowly to their new environment?

Thanks so much for any advice!

[Hank Paloci]

It depends on how big the first batch are. I've read that fingerlings eat fry but that full adults don't bother. I would not put fry in with larger tilapia that can eat them unless parentage is involved. So far my tilapia aren't eating one another but I don't have any fry either. My batch ranges from 3/4 inch to maybe 2 3/4 inches.

[Jim Troyer]

There will always be "pecking order" issues with Tilapia. 

Best advice is to add a screen partition for the new ones to hide behind, better yet, use screen with large enough hole size for the small fish to pass through, that way they will assimilate quickly but have safe haven if need be.

[Gary Wong]

My understanding is that full grown tilapia won't attack fry, but juvenilles might.  150 gallons seems small for 30 tilapia, but I guess it depends on how much grow bed you have on there too.  I'd also feed them often.  Let us know how it works out!

[Mike Bavas]

Appreciate the advice everyone!