Yes it definitely looks like that. You can either break off the entire snail from the rock / coral frag. You can put a bit of superglue over the openings so they starve and die off. Do it before they get out of control.
Looks like you have an aptasia issue as well. Try aptasia x , peppermint shrimp, file fish or a copper banded butterfly fish. Add these with caution as they might not be reef safe.