Yeah, they could but its weird that you see them being sold and they are all grouped together. But then again that is at about 3"- 5" sizes, almost always a lone wolf when bigger.Sounds like you have two males if they are cave dwellers. If they are they could get territorial as they get bigger.
Im not sure what to do with these guys... possibly separate and put one in the 90 and keep one in the 65B? This may not work because I have a plan for the 65B that will include a cichlid that may pick on it. So then I could put both in the 90 and see how that goes.