I had two sebae anenomes which then split into four...and if they weren't so nice looking, and my clarkii wasn't hosting them---they'd be GONE!!! My tank is only 29 gallons, and when they decide to move (and they are ALWAYS moving), it's like a wildfire. They kill everything in their path. But, like I said, they look great. I try and 'corral' them using branch coral.