Predatory narcissus snails

[PaulStrickland]

I have five huge (1.5"+) narcissus snails. I've seen them eat other snails that I figured were just dead or dying, but last night I caught two of them eating a decorator crab that had been walking around the tank just an hour before.

I thought these guys were just supposed to clean up dead stuff! I did some research and concluded that they are not whelks because they burrow under the sand and don't have patterned snouts. And I'm definitely going to re-home them since I plan to have a clam at some point, but in the meantime can you guys tell me what I'm missing here? Pix attached. Thank you!

 

[ISpeakForTheSeas]

The only thing you're missing is that this snail - which, as far as I can tell is Nassarius olivaceus - is called an Olive Whelk, and is known to be predatory.

Most Nassarius species are scavengers/opportunistic predators (only going for dead/dying animals), but this specific species is known to actively hunt prey.

 

[WheatToast]

The only thing you're missing is that this snail - which, as far as I can tell is Nassarius olivaceus - is called an Olive Whelk, and is known to be predatory.

Most Nassarius species are scavengers/opportunistic predators (only going for dead/dying animals), but this specific species is known to actively hunt prey.

Oh no! I have one too that I previously identified as Nassarius velatus, though Nassarius olivaceus seems to be closer in appearance. I have never seen it attack any of my other invertebrates, only uneaten food, though my refugium is always ready for another occupant if something nasty occurs.

 

[ISpeakForTheSeas]

Oh no! I have one too that I previously identified as Nassarius velatus, though Nassarius olivaceus seems to be closer in appearance. I have never seen it attack any of my other invertebrates, only uneaten food, though my refugium is always ready for another occupant if something nasty occurs.

Yeah, not a lot of info on what they eat, unfortunately, so they may still prefer dead foods or be pretty particular with their live prey for all I know - I just know they've been reported to eat snails in a few cases (a few of the shops that I've seen offering these list them as whelks/semi-aggressive/refugium only), they've been documented eating bristleworms (though I don't know if the worms were alive or dead), and they've been documented not to feed on oysters.

 

[SaltwaterAq Verified Sponsor]

In the aquarium, they will eat leftover food, detritus, and etc. Nassarius snails are very good at scavenging. However, if you have many snails or there are not enough leftovers and naturally occurring food. It would be better to supplement their diet with all sorts of meaty food, like frozen brine shrimps, freeze-dried larvae, and cut up pieces of fish and seafood. Otherwise, they can turn cannibalistic.

 

[19Mateo83]

I ended up getting a predatory Supra Tonga one. I’m convinced that they all can be predatory.

Super Tongan snail NOT reef safe!

I have heard pretty much everyone say that the Super Tongan Nassarius Snails (Nassarius Distortus) are reef safe. In this video I watch one not only eat a piece of food stuck in a zoanthids mouth but it also eats the top of the polyp off too! I don’t think these are quite as safe as everyone...

www.reef2reef.com

 

[WheatToast]

I ended up getting a predatory Supra Tonga one. I’m convinced that they all can be predatory.

Super Tongan snail NOT reef safe!

I have heard pretty much everyone say that the Super Tongan Nassarius Snails (Nassarius Distortus) are reef safe. In this video I watch one not only eat a piece of food stuck in a zoanthids mouth but it also eats the top of the polyp off too! I don’t think these are quite as safe as everyone...

www.reef2reef.com

I have both Nassarius arcularia (the species you had) and Nassarius distortus which never caused me issues, though I do feed very heavily.

 

[EeyoreIsMySpiritAnimal]

I have both Nassarius arcularia (the species you had) and Nassarius distortus which never caused me issues, though I do feed very heavily.

Correct. Aside from a Donner-Family-type situation, N. Vibex and N. Distortus are pure scavengers and will not harm healthy creatures.