It will outgrow a 125 in time. Be sure you have a place to take him when that happens! Reef Nutz is right -- it doesn't happen overnight, but panther groupers are much faster growing than a lot of the other large predator fish. I really don't think they should be sold in this hobby at all. They are caught and put up for sale so small, and it's so misleading. I'd bet that 99% of the people that buy them cannot provide for their needs long term.