When he was little Mouse got to try a few different treats but turned his nose up at all but Thrive white fish snacks. Thankfully as they are 100% fish freeze dried, and not too hard and jaggy like some of the freeze dried snacks I've bought, he still gets them: they don't seem to upset his dental routine and he can still manage them if his gums are a bit sore. His other treats are his poultry flavoured enzyme toothpaste when he gets to lick it off the finger brush, and getting a drink of water from a syringe.
Funny boy.