Yes, I have a male betta in my tank with two 8" goldies. Bing keeps them in line for me. Betta Bing guards his territory but never tries to fight with anyone. Generally when I have to put my hand in the tank for some reason he actually glides thru my fingers. Talk about a personality!
Thanks for all the thoughts about the wheels folks. The 125 that I am putting in is going to be on a wood stand. I am looking at wheels that can hold the weight, place them strategically on the bottom of the stand to balance the weight, and be sure they can lock. I don't want the tank moving just by someone walking in -- that would be bad.