Here I'll talk about good cages, bad cages, and how to get the recommended cages.
Not Recommended
Aquariums
First and foremost, this is the type of cage that you should absolutely avoid. Rats have very sensitive respiratory tracts, and because there is little to no ventilation in an aquarium, it will easily cause respiratory issues. People tend to just get them because they are most likely uneducated and don't know otherwise.
Also, people will sometimes get a "topper" for an aquarium, like in this picture:
I still do not recommend getting something like this. I wouldn't want my rats in an aquarium at any point, really. Not to mention, there isn't a whole ton of room for them to move around in.
Most Pet Store "Starter Cages"
Okay so not all of them are bad, but most are. A lot of the time you will see a starter cage that has one level, and isn't the right size for more than one rat. The only time that I would recommend getting a starter cage is if you're going to use it for travel, or you're going to use it just as a temporary cage (such as using it as a quarantine cage). Some will have a little "second story", but it's really just a shelf -- still not enough room for more than one rat.
 |
| Now for this cage, I would use it as a quarantine / travel cage. Just as long as it's not permanent. |
Recommended Cages
Critter Nation / Ferret Nation
These are my absolute favorite cages you can get for rats. They are spacious, provide plenty of ventilation, have a lot of room for quite a few rats, and you can add more units to it to make it as large as you need. They are fairly easy to clean, and there's so many ways to make the cage a very enriching environment for your rats. Of course, they aren't the cheapest cage you can get, but they are worth every penny in my eyes. You can always search Craigslist to see if there are any near you that you can get at a much cheaper price than buying new. You can also search for a Ferret Nation, the only difference between the cages are that the bars of the Critter Nation are horizontal bars that have 1/2 inch bar spacing, while the Ferret Nation has vertical bars and a 1 inch bar spacing. You can hang a lot of different toys from the bars, and hang up hammocks.
 |
| Image Credit: http://www.moonlitwatersrattery.com/ratcare.html |
 |
| Image Credit: http://www.ratshackforum.com/forum/showthread.php?t=23862 via crumbilina |
 |
| Image Credit: http://www.rattyratrattery.com/ratty-care.html |
Martins Cages
I have never personally owned a Martins cage, however I gad heard good things about them. They aren't as spacious as the Critter / Ferret Nation, but they have some good sizes. Here is a link to the site where you can buy the cages. There are many different types, and don't feel like you have to stick to the rat cages! Experiment, and look at the sizes and what would fill your (and your rats) needs. The only downside that I have heard about these cages are that they can be a pain to clean. Again, I have never used one so I can't tell you how easy or hard it is to do so.
Tips
I mentioned it in the Critter Nation section, but you can look at Craigslist to find a used (or, if you're lucky, a new one) cage. If you manage to find one, make sure you get pictures of it or go check it out in person before you go to for sure get it, because it could be broken. But if you snag a nice one, good on you!
If there is a cage you have or are looking to buy, but don't know how many rats can fit in it, here is a rat cage calculator! It's very useful. If you are really unable to afford a larger cage, just make sure that you let your rats have a lot of outside the cage playtime!
I hope that this was helpful, and if you would like to ask me anything, shoot me an email or leave a comment!
