I would NOT attempt to keep a Jewel with any other fish unless you have a spare tank to move one or the other to. I have experimented with different fish and only found a few that the Jewel will tolerate. But you have to understand, I have a 10g, a 40g, a 55g, a 65g, and a 75g. I can move fish around as needed if compatibility is off. You should not do this as I have a very unorthodox method of handling my fish. I am prepared to deal with the problem when they arise. I can definitely say that A LOT of people advised me to take the Jewel back. She is hell packed into 4 inches. Your friend got very lucky.