I have 6 of these delightful little guys. They are a riot to watch, and what I really like is that they play during the day right out where you can watch them. They spar with each other. When mine get - what? bored? Joyful? ;) They school with the glowlight tetras and/or the otos. Just swim right along with them like they're part of the crowd. This morning they are going up and down the tank glass with the Julii Cory school. I love them! I forgot to add that they are slowly but surely wiping out the snails!
I have six of them currently, they will actually shoal mid-water, and are active during the day. They haven't bothered my nerites and they've both been in there for months, nor have they bothered my amano and ghost shrimp. They are schoolers, so you really need at least five for them to be happy, but they're fun to watch. Mine seem to think they're rosy danios, they swim with them often enough, anyway. Seems to rather confuse the danios. The only caveat I've found is that they will COMPLETELY out-compete cories (as in the cories will slowly die of starvation because they can't get enough food). They fill the same function, plus (small species) snail control. They can't seem to wipe out my MTS (though they do knock them back), but they completely eliminated my pond snail problem. Batch is correct -- 2.5" maximum length.