Transporting a Firemouth

How big is it?

If you could, I would personally get the standard 5G bucket, wrapped in blankets/towels to avoid heat loss.
 
Don't forget to stop for a second and stir the top of the water creating more oxygen into the bucket. I moved my fish and it took 12 hours, but when I stopped for gas I would stir the top of the water and do a small water change to help out removing ammonia and stuff i nthe water.
 
I ended up using the cooler idea.

Here's something related, but a bit off topic:

I had to move the fish because it was getting beat up in its old tank. I moved it to a 10 gallon (temporarily). How long do I have to setup another (bigger) tank before the 10 gallon harms this fish?
 
You probably don't have that long. I would say you have a couple months at most. Just remember, a smaller tank won't necessarily harm the fish physically as long as water is kept in check. Just make sure that you get a 30 gal. or more so the fish is happy.
 
I definitely plan on getting at least 30 gallons, and I'll definitely keep the water in check. I just wanted to make sure I wasn't stunting growth or anything by keeping it in there.
 
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