Having lost my angels, I have been looking for some open-water swimming fish for my main tank. I have been considering tetras or White Cloud Mountain Minnows for the last couple weeks, but nothing really jumped out at me. So today I finally decided to go with Glowlight tetras, Hemigrammus erythrozonus. I wish I had made the decision after careful consideration of the biology and behaviour of the species, but I actually just narrowed it down to the ones I liked most, and based my final choice on the tank that had the healthiest-looking fish. That said, having spent two weeks looking at what was available locally and ruling out the ones that seemed too prone to fin-nipping, the decision wasn't just based on a whim. But neither was it the fulfillment of my quest for the "perfect" fish to fit my needs.
That said, I'm pretty happy with my choice thus far. They look pretty good in my tank, and they are schooling nicely. They're quite active and add colour to the tank. Unfortunately, they appear to prefer the lower third of the tank. They are venturing into the upper parts of the tank, which is encouraging - hopefully, as they grow more comfortable they will make more use of those areas.