Ohh I see, I thought you might jsut have him in a bucket.
they optehr thing you are missing is the liverock which also does filtering for you. you migth be ok for now with just the filter, but I'd try to get your tank figured out ASAP, more water changes soon, and get him back in there.
make sure in the bucket that the powerhead is pointed towards the surface of the water enough to cause some waves on the surface, this will improve surafce area. The more waves the better.