Kay is right... I didn't even notice the mention of an aquarium until reading the post above, and then, after re-reading the original message, I see.
An aquarium is okay only for temporarily housing until a more suitable cage is aquired. For example, when quarantining new rats, if the actual quarantine cage isn't available(such as now, when one of the hamsters is calling it home), I use an aquarium, as they will only be in it for 3-4 weeks.
Even with regular cleanings to keep the ammonia level down, aquariums typically don't provide enough for the rats to climb on. Rats love tall cages where they are able to climb up and down the side, to many different levels. My boys like for me to scratch their tummies through the cage bars when I pass by the cage. =D
And also as Kay mentioned, homemade diets are typically better, plus, your rattie would enjoy it more. After I switched mine over to the homemade diet, they will stick their nose up to the mixes that are aquired through a petstore.

I forgot to ask, if this hasn't been asked already, do you plan to get another male rattie for Winkie to be friends with? Rats are pack animals, and even with alot of human attention, most crave attention from their own kind. Eventhough Winkie only has one eye, he should be fine with a friend, especially if the friend is introduced at a younger age. Disabled rats do perfectly fine! My Sid has a neurological problem so that his balance is horrible and he just.. well.. doesn't think right. He is housed with 3 other males(soon to be 4 after quarantine is over) and he does perfectly fine.

Sorry for such a long reply. I get carried away sometimes, especially when talking about rats!