It's some sort of tetra. Maybe an albino variety? I can't see its eyes too well. Looks similar to a black skirt tetra to me, though without the black skirt. I think my LFS sells a golden skirt tetra. Maybe this is one of those?
They are very hardy fish whatever they are before I bumped to a 29 gallon they were in a 10 with a few mollies and and some guppies but I had a horrible ammonia spike that killed all but my breeding pair of mollies pongo and perdita , (I was over stocked) and I must admit my 29 gallon is over stocked but I have plenty of hiding places and interesting features, plus a tetra ex 45 and a 20 gallon air driven filter they all seem happy and yes my small shoal of 4 Cory's are so cool! Haha thinking about bumping it up 2 or 3 more. Wanna see more pics of em
Btw the first pic was my small tank before I upgraded, I now use it for brine shrimp and breeding snails and such quarantine tank aslo