I have some of these in 1 of my tanks and they're doing really good job moving sands.

Now I want to distribute them to other tanks as they're multiplying so fast that they can be spotted everywhere. However The big ones rarely appear and if they do, they stay in rocks/plants that hard to reach.

Are there anyway to lure them out? I know there are many big ones as small ones are everywhere!

They congregate on lettuce/cucumber slices in my Oto tank

I'll try that!

By the way are they nocturnal?

I'm always hoovering them (and the substrate) up by accident when I do water changes. Put the substrate back through a sieve and you'll collect the snails, and you can then pick them out and transfer them.

Scooping through the substrate with a sieve is a good way of picking them up, and will help turn it over to if the snails haven't quite managed it.

they become more active at night, not truely nocturnal but close enough