They are a lot of fun now. :-) I play with them like adults and, though some of them are still afraid of things (sudden movements, noises), they are becoming fearless and very comfortable with hands and vacuum cleaners and other things. I love watching them interact with each other, cleaning and wrestling. Sometimes there's a ball of four or five of them "rolling" around the aquarium. As you can see above, I've put lots of fun cardboard things in there but not too many (they like room to run around).
I also have fun playing with them myself. You can see in the following pictures. I'll explain. The fist picture is "calling." I scratch the ground and the pups come to investigate. I call my adult rats like this too. Sometimes I tap the ground or talk to them to get them to come. The second picture is "hand wrestling." I tickled them and chase them and push them over just like they do with each other. They really get into it and will hop around and pounce on my hand.
They are eating and drinking A LOT. I have to refill their bottle almost twice every day. Baby rats can eat more than adults so we give them lots of the regular food and lots of table scraps too (especially fresh veggies, bones, and noodles).
You may wonder exactly how big they are... Well, I've always found this reference to be one people can relate to:
I have narrowed down my choice of "keeper" females. It will be either Echo or Elixir. It is so hard to choose! (This is Elixir who is calm at this point from her nap.)
Here are some other close-ups. Eve and Euclid.