Snail id

These were on my rock not sand I think they were born in my tank they are only about 3/8 inches long right now but i dont think they are nassarius because i had a snail that was eating my astrea turbo snails kind of looks like this but not really. And i captured these and when put in a holding container a few baby turbo snail shells fell out with them so I'm trying to be curious before i put them in another tank
 
still look like nassarius snails to me. Throw some sand in your holding container and a sacrificial tubro snail. If these guys bury themselves in the sand and your turbo makes it through the night then I think you are safe.
When you feed to they all stick there "tube" looking thing in the air and start to make there way up the glass?
 
Thanks i threw some spirulina flakes in there they didn't touch it as they're just on the walls of the container I'll try the the baby turbo sacrifice tonight
 
Thanks guys just did a bit more research and whelk was my guess from the beginning. I wanted to be sure first these are a type of whelk called pollia fumosa. So if you have any small or big with the stripes like these they are predatory and they do hang out on the rocks which is where I found these. Again thanks for the responses. Here's a link http://www.gastropods.com/6/Shell_796.shtml
 
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