I've got a sheet of exercises from when I was having my hydro sessions at the rheumatology unit, I'll see if I can dig it out and scan it.
Of course you don't need any joint or other problems to benefit from exercising in water, the water supports the joints and increases resistance making the exercises a little harder.
Water exercising can be quite tiring, hope it all goes well defirish
EDIT: Hmm sheet isn't in the folder I thought it was..
Here's some exercises listed online a few of which were on the sheet I had. Hope this helps. If you're unsure about doing any of these always ask your GP or specialist/nurse.
Back pain warm water exercises 10 exercises to get fit in water