Well I bought this beautiful fish 2 days ago and added it to my 165. Then yesterday i noticed the little texas chasing the new fish and this morning when I went to work it was dead,,,,,,,,,, Guilty: TEXAS
No wonder it was killed...sorry to hear about the loss, but a little research would have told you that putting a G. altifron with a texas would likely end up that way.
You are correct, Hecklii are more aggressive then most geo's so considering it was about 5" and the Texas was only about 2.5" I thought it could work but obviously it didn't.