55 gal tank

I have an aquarium that is 48” L 12” D 21” H. My immediate assumption is this is probably not a good home for a hamster.

Some context… I’m phasing out of goldfish. I have one little guy left who doesn’t seem to like all the extra space. I think he doesn’t feel very safe being the only fish in the big tank so I’ll be moving him into a smaller home, or rehoming him. They’ve been fun, but I need to take a break from large aquariums as I’m struggling to maintain the filtration. But, my family has asked me if I might bring home a small fuzzy… Specifically, rats… which I’ve had in the past, but the whole point of asking me this is because we recently had to put our family dog down and my family thinks it would be good if I had a furry friend. I love taking care of animals, I’ve had some experience with mice and rats and I love them. It’s just been a long time.

I have NEVER had a hamster and never heard great things about them (compared to rats) so I’ll be doing loads of research before I take this idea seriously. I just want to know what you experienced people think, and if this tank would be a suitable home once it’s drained?