I have a CNBG only nursery pond. In 2005 I harvested 1925 CNBG. In the spring of 2006 I added Tilapia. In 2006 I harvested 2650 CNBG and 525 Tilapia. From this short test it looks like the Tilapia did not affect the CNBG reproduction. Will do the same in 2007.