hay is not digestible for rats and you might want to reconsider taking some farm hay...that hay may have had wild rats run over it and leave behidn their special friends, rat lice and mites and your rats can catch them.
You need MORE things in those aquariums, plus tanks are considered NOT good for rats due to ammonia buildup (they need to be thoroughly cleaned every 2nd day). I think you had better start investing in wire cages with LOTS of levels...people are always selling used cages online so start there, if you don't want to order from martinscages.com etc.
I used to keep rats in aquariums a LONG time ago, when I didn't know better
, didn't have the internet, etc...my cages looked like yours, a box, waterbottle, food, and bedding...no wonder my rats died of URI more often than not, but they did get out and run free for hours at least.
There are a ton of cheap toys out there at the dollarstores...children's link toys for a buck, etc. Make your own with wood blocks, a drill to drill holes through and hang them in your cages. They can chew or shove them around, etc.
Right now I have over 70 rats, rescues, fosters, etc...but all my rats are in wire cages with levels, toys, beds, hideyhomes, etc...
And there's ONLY me to take care of them all.