Yesterday I moved my little container pond inside for the winter. I have three trapdoor snails I would like to save, but the new location is in the basement where the pond will get minimal light from a couple of window wells. So without algae growth in the pond, how do I go about ensuring they have enough to eat for the winter? What I can think of is tossing a few leaves of wilted lettuce in there once per week. Is that the best way to go?