Probably the mellowest medium-sized cichlid I ever owned. I had one for about 10 years, kept it with small tetras, danios, barbs, it didn't care. Grew to about 5" and lived through all sorts of adventures, including a several year stint in my mom's 2nd grade classroom. Also one of the drabbest, being a boring grey-brown, but had a nice scale pattern. However, I never put any effort into finding a mate and breeding it, so that may have changed the color and behavior completely.
I'd say you easily have room for a pair in your 37.
edit. Just checked the site, that doesn't look like any port I've seen. Ports look more like the pic in
The Cichlid Room Companion. I can't link to it, so go to the South American gallery, under Cichlosoma portalagrensis. The LiveAquaria fish looks like what we used to call Aequidens dorsiger, and is now called
Laetacara dorsigera. I'd say dorsiger/dorsigera would be an even better score, so go for it.