My friend has asked me if these are ok for her aquarium to control pest snails and clean algae. She is worried though because she has an aquarium without a lid. Do they ever try to venture out of the water?
Assassins are great and they don't seem to eat the larger nerites. I haven't tried keeping either in an open top tank both climb but the nerites are especially adventurous and I do sometimes find them above the waterline.
I looked into this a while ago. Apparently assassins will attempt to eat all other snails. Nerites are able to completely close off their shells and this makes it difficult for assasins to get at them so it is likely that they will only attack them if there is no other food source available but not guaranteed. I decided to veer on the side of caution and not keep both together.