No, they are cichlids. They are extremely peaceful, but also very curious, and mine have stressed very shy fish just by their curiosity. I keep 2, and I believe them to be a pair although they haven't spawned. The males max out at about 4-4.5 inches, and the females are a little smaller. These fish change color according to their mood- they get very dark and blotchy when stressed. Mine look like the top pic in the link.
A word of caution- these fish WILL look darker with black substrate. I keep mine in a tank with pool filter sand, but I used to have them with black gravel. There's really a difference in the way they look with different substrates.