The store I got him at had 3 in their tank. I asked the guy to feed them, he was more than happy to. He told me that most people just pick out the prettiest/brightest and go home. He threw in some beefheart and all 3 went nuts for it. From there, I picked the one that stayed at the front of the tank, even as he was scooping water to put in the cooler.
We chatted back and forth for about 45 minutes about our different setups. Even though it's 45 minutes completely out of my way, even from work, they will definitely get more business from me.
*edit*
The guy told me that beta carotene (sp?) helps retain the red color. Any truth/experience in this?