But if it's a new frag he just bought, nuke it. If you have access to a syringe and a needle, inject if with microwaved vinegar. They melt away and are gone for good. You can pull the frag and do it in a bowl of tank water, but I just did it in my tank. The vinegar dilutes quickly, and it's only like a teaspoon you'd use anyway.
Later,
B.