If you want a green terror, I say go for it. Mine was a great fish and was easily one of, if not the most beautiful fish I've ever had. Also, once he got big, he never bothered any fish that he didn't see as threat. I will tell you, he did go through phases though. Sometimes he would be very outgoing and sometimes he would still act a little shy. Another thing to consider is that this tank would be pushing the limits on size. If you were wanting to possibly do a pair I would go with the jack Dempsey. They normally bond well and I've never had a Dempsey pair that showed aggression towards each other. They tend to be lurkers though. However, I kinda like that about them. What ever you do, I wish you the best of luck. Oh and there is nothing wrong with swapping out fish every now and then. This hobby is meant for our enjoyment and if you don't like your fish, you won't like your tank and it defeats the purpose of having one.
-JMart
-JMart