I've got a dilema of the not so serious kind, yet it makes me anxious. I'm going to trade my swordtails in for some kuhlis, and ttoday I found out one store has only the black variety and another store has both. I can't decide which type to get. I had my heart set on the banded type, but i've heard they can be less hardy than the black variety. I was also wondering if it is possible to put two banded and two black together. I don't know these two types tolerate eachother.