I have a blue acara in my tank and he is a really cool fish! I got him cause i wanted a GT but didnt want to risk a GT being to wild for the rest of my fish especially my BGK, he shares his tank with all the fish listed in stick list mentioned below...when i got him he was no more the 2 inches in with a full grown oscar.... he can be a bit bossy to others at time but the other fish usally move out of his way and there is nothing more to it. The only time a ever seen any real agro from my BA is when i had a JD in my tank for a couple of days, i was holding if for a friend. The JD and BA were about the same size and looked really similar, my BA gave the JD a hard time and left the JD with a few marks, they JD wanted nothing to do with it and hide the whole time, i think the BA confused the JD for another BA . I am hoping to upgrade tanks soon and want to get a JD of my own just hope my BA will let him stay in the tank.