I love IJ's and have good sized group of them. Some of mine are very active and others are very inactive - seemingly never moving. I chalk it up to the individual.... One of my adults is constantly cruising his tub and I mean constantly. His sister is one that hardly ever moves. All are very healthy and range in age from a few months to three years... Now that I'm thinking about it..... My younger ones seem more inactive than the older ones..

P.R