Well, I have a story to relate.
Bought some glowlight tetras about a month ago and noticed in their tank in the shop was a pretty little fish with no species-mates, as it were.
Popped in there again yesterday and the poor little thing was still there so I decided to buy it. Didn't know what it was.
When I went back to collect it later, the lfs lady said, "Oh, I saw another one in another tank." I had also thought I'd noticed one earlier while browsing but, try as we might, we could not find the bloody thing.
Anyway, I trotted off home with the fish.
This morning, I popped into the lfs and lo and behold the other one was staring at me from a tank full of barbs.
I bought that too. I now have two of them and they are my new favourite fish. Turns out they are Blue-Eyed Rainbow fish and I'm smitten.
I've ascribed a vulnerability to them which is making me so fond of them and even more so because they're holding their own in my tank of silver-tip tetras, glowlights, cherry barbs, corys and angels.
I tend to go for small, pretty and subtle rather than garish, weird or big.