malasian trumpet

I am starting to have a Mts problem in my pea puffer tank. The puffers do not eat these. is it safe for me to put lettuce in the tank to attract the snails

So, a month ago I put a melon sword in my gourami tank. About 2 weeks after that I noticed some Malasian Trumpet Snails crawling around, so I've been keeping an eye on the little hitch-hikers to make sure they don't take over. However, I found none today. The only occupant of the tank is a male...