Hi, I hope this is not a stupid question, but I was trying to select fish for my new tank and would like some tetras. From the information I've read I have found out it's better to keep them in shoals of around twelve. My question is would the shoal have to consist of the same type i.e. all neons or could I for instance have 4 neons, 4 glowlights and 4 diamonds? Would they be happy together or are they sworn enemies? I new to this so be gentle.