My sister set up a tank for her daughter and doesn't know much about fish care. I'm trying to give her a hand, but I live a few states away, she has gotten the tank cycled and they added these fish - the receipt at the store said zebra tetra - which I'm not familiar with. They now have ick and I was going to tell her about treating with heat, but she's already started a chemical treatment. Any clue what fish these might be? They were not ones I was familiar with - and I don't know what a zebra tetra is...