Diet For Snails

I would drop in an algea tab at night. or if you really want to make him happy, a piece of blanched spinach or cucumber, zuchinni or lettuce.
 
If you've got an apple snail, they'll eat just about anything, and lots of it. They're omnivores and can consume a surprising amount. Check out www.applesnail.net for loads of info on all kinds of big aquarium snails.
Snails are great scavengers - they'll eat algae, leftover fish food and anything else edible. I see my baby ramshorns munching away at surfaces that look clean and algae-free to me; I suspect they're eating the layer of bacteria/algae that builds up on everything in the tank.
 
Assuming you aren't trying to suplement anything in particular, Blinky is correct. snails can actually live on bio-film only long term (or at least the ones under my RFUG plate seem to). They will eat virtually anything, and all of it they can find. If you want to add some high calcium stuff to their diet, Hikari Crab cuisine is great for them, so is a piece of cuttlebone tied down somewhere in the tank.
Dave
 
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