Need help with rats....

To make a long story short i had been talking about starting a colony, and my "helpful" brother overheard the comments i was making. He went to work and a guy he works with keeps snakes and he bought 2 feeders, the snakes went off feed for 2 months and he ended up with 2 litters totaling 18 babies. I now have 4 of the fairly small rats. Unknown to me they were coming home tonight, and i purchased a med/large rat to feed this evening (and my snake wouldn't eat). Now comes the part I need help with, I don't have anything set up for them and they are in the small carriers(4 small ones in one and the large in another). Can i keep them effectively in a spare 18 gallon tote? i also have a 55 gal. aquarium that is empty if that would be better. I don't know much about rats yet, but am i correct that i have to keep the larger one separate from the smaller ones? All help is appreciated

If you can't feed off the larger one, it would be a good idea to give them a partner of the same sex. Rats need buddies since they are a highly social creature.

If you can, set them up in the 55 gallon, 18 gallon tote is too small if I remember correctly.

Here is a link on how to make a rat tub. Most just put the mesh in the lid, but this one puts it on the side for cross ventilation.
http://ball-pythons.net/forums/showthread.php?t=56321