a few years ago I tried giving my loaches a piece of cooked Italian pasta* and the response was very positive, they seem to really love it. One or two pieces are more than enough for 20-30 small to medium sized fish. I do this regularly now (1-2 times a week) as an alternative food and never observed any negative effect from it, except for very full bellies (omnomnom).
So, the next time you're having pasta try giving some to your loaches too. It's a sight to behold to watch a loach swimming away with a piece of Farfalle in its mouth.
Since this is basically pure wheat I can't see any negative health aspects either.
*I use Barilla pasta made from 100% semolina (wheat middlings of durum wheat).