Good question on the floating snail. I didn't have snails when I had my guy. Not sure how he would act with them. My guess would be if he did take one in, he would spit it back out. Mind you....that is just a guess.

As for the neon replacement, not knowing your tank and such but if you're looking for a good mid-level schooling fish, how about some Harley's (Harlequin Rasboras)?