Hi everyone, I'm eventually planning on building a plywood tank around 8x4 specifically for rays and some other fish. I really don't want to cramp the fish at all and want to also make sure I keep the parameters in check as I know rays are sensitive, so I was thinking about getting only 2 rays. Since females tend to get way larger, would it be ok to house only 2 males together? I don't know if this would cause any aggression between them, or if rays prefer a certain male/female mix like some other fish do. Also, would it make a difference if they were the same species? I'm set on keeping a black diamond, but was considering getting a motoro as the second male, would this make possible aggression between them a little bit better? Thanks in advance for any help, any other info would be greatly appreciated as well from some experienced ray keepers!