after reading about cone snails, (thanks @Fishbait) I am now worried about the 2 "Nassarius" snails I have. I bought 1 from the fish tank so I assume it really is a Nassarius (plus he's somewhere in the bc29 right now) but this one came with the new tank and I'm finally getting to moving the last of the critters. I definitely want something reef and human safe! It's about 1.5-1.75" I'd guess.
Well when fishbait posted about the cone snail it got me googling because I wasn't familiar with them and wanted to learn something. Well this led to reading that many Undesirable whelk snails were being sold as Nassarius snails. And so I wanted to look this guy up before adding him since I didn't buy it. The closest thing I've been able to find is the Nassarius olivaceous and I seriously can't find anything more than a description of the shell. No information on them or if they are reef compatible. I just really want to know exactly what it is and be able to look it up. Not all Nassarius varieties are good ones.
Whelks do look very similar to and are related to nassarius snails. One way to tell the difference is to watch it's behavior. Nassarius sleep in the sand (sometimes sticking their probocis out) and emerge when you feed the tank, scouring the sand for left overs/detritus. Whelks are predatory and kill other snails. If you see it on the rock work prowling it ain't a nassarius. Check out the hitch hiker thread that's stickied in the General Reef forum. That should have pics of both.
Yep, I looked right after I posted that. Lionfishlair posts on R2R and is on staff there. You could try posting your picture there. If you get a side view instead of the top down view it would probably be better.