shoal

I'm looking for advise on a shoaling fish for my aquarium, that will not be eaten by my Rope fish, the tank is 55g at the moment. Something that gets 4-4.5'' in length would work best, nothing that is too aggressive towards other tankmates Planted, sand substrate, any information will help.

Which (small, community) fish form the tightest, most coherent schools/shoals? Opinions? Experience?

I recently added 8 neon tetras into my 52 litre tropical tank which has a few guppies and cories. The tetras shoaled for the first day - still scared I assume - but now they have settled in they are all over the place. I much preferred it when they where shoaling but how can I make them shoal...