My 5 month old kitten enjoys the “bubbler” and watching him play with it learning to drink from it was laugh out loud entertaining, if a little messy for a few days.  Now, he drinks from the reservoir or the bubbler.  I find the occasional toy in the reservoir, but only rarely.  I joke that he must’ve been a plumber in a previous life because he loves watching water go down the drain so I expected he’d enjoy the Pet Fountain.