Nassarius aren’t super predators. I have several species that can’t right themselves in there with mine and generally I catch the ones that have fallen before they’re able to eat them. Spiny nerite snails, cerith snails, and margharita snails all coexist fine with my nassarius.
The ones in the picture aren’t. Whelks have a tattoed trunk and a trap door that closes when they retreat into their shell that you can see on the end of their bodies when they are moving. Whelks also have a sort of different shell style. Or at least mud whelks do. Hard to explain without having one in person for me to take a picture of.
Why specifically spiny astrea? I've never actually kept those-- only the standard astrea.
Well, they seem to only prefer the rocks (along with ring cowrie) - whereas the trochus love the tank sides and the nassarius the sand bed.
Spiny astrea are natural tanks as well. They have a door and their shape means it’s really hard for them to fall over in such a way that they won’t be able to right themselves.
