about 6 months. so far so good, but I fully understand that the results aren't typical. I've seen my BTA's lying on top of my haddoni and my LTA without any problems. The LTA and the haddoni are on opposite sides of the tank, so I don't expect they'll touch each other. The haddoni is about 18 inches in diameter. I make sure it doesn't get fed any more. It's doing well. The LTA I put in 6 months ago. I got it really small and try not to feed it to much (knowing how large it will get), it's continued to grow but is still only around 8 inches in diameter now. The BTA's all range in size some green, some red. So far all are doing well. I have had some color issues (bleaching) with the BTA's when I switched from MH's to LED's, but I've since switched back and their color is slowly returning to normal. I run carbon, biopellets, and purigen.