Must be 12 years ago I bought 4 red scissortails on impulse. I never much cared for common scissors but the reds looked nice and I knew they grew larger. They got to nearly 7 inches and they were stunning when they were adult. I wanted more but have never seen them on sale since. I've lost 3 of them in the last 2 years so now have just the one left.
Also , 3 years ago I bought 6 Alestes Tetras (African Long Finned Tetra) mainly because I wanted some large tetras. They too look fantastic now that they are 5 inches long and we'll settled. My LFS didn't have very many when I bought them and after my 6 they were left with about the same number. The last time I went to the store a few weeks ago they still had them! They are quite expensive at £8.50 but if people realised what they look like when they are settled, surely they would sell.