safe or predator snail?

[Marc G-L]

UNS 125 gal tank. UV, fuge with amphi and copepods plus Ulva, GHA and a little red dyno patch.
I bought a few of these ( see video) from my LFS. They called them large snorkel snails. They do remain in the gravel until nighttime, or if feeding tank and a fair amount of particles are generated, they surface. Do great job of moving 3-4 in DSB. Looks like Godzillia pushing up gravel as they rise. Shell shape live an Olive snail but have that long breathing tube. I've unexpectedly lost a few mex turbos, astrea snails and a larger Halloween crab in the past month. All params are stable and with in range except phos. It did hit 0.46.
Got that down with 30% h20 exchange and phosguard. Only worms in tank are a few penut worms on glass and 2 ghost worm planaria 4 months after start up.

 

[Baldyreef]

olive snail, if i were you id take it out, they clean out all the fauna in your sandbed and will definetly go after your clean up crew

 

[Marc G-L]

Yup predatory Olive snails. Clearly I'm done w/ the LFS that sold them to me as reef safe large snorkel snails. Tonight is safari night. Hunting big game Olive snails.
This morning I discovered more carnage, another Mexican turbo snail and a Halloween hermit crab eaten/ attacked.

 

[Baldyreef]

 

[Marc G-L]

It will be a slow torture as payback

 

[Baldyreef]

gotta avenge the Halloween crab

 

[Marc G-L]

Final note:
A very large pithos crab, several giant Turbos and a few ceriths fell to the 2 olive snails before I could capture them. Several of the large turbos were found alive but, languished. They stayed partially out of their shells and would close up if touched but, did not graze like the hungry wolves they were days before.
They eventually died. Looking up how Olive snails kill their prey, it turns out suffocation of small prey. However....poisoning/ paralysing them with their proboscus if prey is too large to suffocate. I can rebuild my CUC now and get the tank back in balance. Case of the mystery deaths solved.

 

[Baldyreef]

Final note:
A very large pithos crab, several giant Turbos and a few ceriths fell to the 2 olive snails before I could capture them. Several of the large turbos were found alive but, languished. They stayed partially out of their shells and would close up if touched but, did not graze like the hungry wolves they were days before.
They eventually died. Looking up how Olive snails kill their prey, it turns out suffocation of small prey. However....poisoning/ paralysing them with their proboscus if prey is too large to suffocate. I can rebuild my CUC now and get the tank back in balance. Case of the mystery deaths solved.