It's actually a small about 2L size hang on breeder box. No plants.erbear said:It depends on the size of your tank. Snails can be a positive part of a tank ecosystem but snails have a large bioload for their size. Also, snails need their own food and can't be expected to vacuum up all the uneaten fish food.
To answer your question, yes. Since snails will convert some of the leftover food into new growth and most likely improve water quality and tank health (assuming the tank can support the bioload).
What size tank do you have? How many fish? Is your tank growing plants?