What Killed My Snail? with pic

[Beverly]

Over the last few months, have had a variety of snail deaths in my 120g. In an effort to reduce them, have boned up on reef chemistry, found a new home for a snail eating dwarf flameback angel, and removed two different hitchhiker snails. All have had positive results.

However, I am still finding dead snails in one specific place in my bare bottom 120g when the lights go on. These snails are either picked clean with no body visible or there is a jelly-like substance around the partially decaying body. There is also a jelly-like substance surrounding the dead snail that collects detritus as well as fine wispy jelly stuff that also captures detritus.

Pic of the snail I found this morning. Notice the wisps of jelly surrounding the snail and the detritus caked to the snail's side:



Any idea what might be killing these red banded astrea snails? If so, how can I catch/kill the snail killer?

Have also posted this on RC. TIA for any insight into this problem