hi there! I'm totally in love with these little guys. I originally read that they were a rainbowfish, but now I think they're a completely different species maybe? I'm not really even sure! I do have some questions though. 1. What is there temperament like? 2. What would be good tank mates if I had a school of 9 of them in a 37 gallon tank? 3. How easy/difficult is it to get them? Thank!