first off, a panther grouper will get waaaay to big for a 55. more than 1/2 the lenth of that 55 at it's full growth. I also wouldnt recomend keeping if it you are attached to those clowns and dont want to be saying goodbye once it gets bigger.
I, personaly, think it is pretty irresponsible (for the most part) for most stors to sell panther groupers. jsut about all of the ones i have seen in stores are sold at about 3 inches or under, which gives the buyer the impression that their tank is large enough. But in time, these fish can actualy reach lengths of about 30 inches! the average aquarist doesnt have, or even have the room/money for a tank large enough to hold one of these, and from what i have seen, most stores do not warn their costomers about it.
I would find a larger home for the grouper.
or if your mom likes him so much, convince her to buy you a 220 gallon :dance2: