Howdy - Dan and Heather here! We love our magenta mystery snails - so when one of our cheerful little friends found herself stuck in the slits of our filter inflow pipe, we tried our best to help her out of the sticky situation. We're writing this just in case it might be of any use to other aquatic snail enthusiasts who find themselves on the edge of a similar disaster. If you are in a hurry, here's the punchline: we chose to break our glass lily pipe inflow and "saw" the pipe apart at the slit using a metal file. She somehow lost a small chunk of foot in the process but seems to be recovering well. Read on for the more detailed story.
The setup:
We recently separated our pair of mystery snails into separate tanks after seeing them in the midst of baby-snail-making. The snail at hand is roughly 3.25 cm/ just over 1.25" in shell length and was in a tank with a canister filter and lily pipe inflow and outflow. We had seen her cruising over the inflow pipe several times before, and had even gently plucked her away from it when she seemed to be lingering too long.
On the afternoon of the incident, we noticed the snail paused over the narrow slits on the intake pipe, presumably looking for a snack. Given that she had seemingly had no trouble moving along before, we left her to it. Come 8:30 in the evening, she was still parked over the pipe, and it now became clear that a sizable portion of her foot was already through two of the tiny inflow slits. Clearly, something was amiss.
We first turned off the filter, hoping that the lack of suction would free her. When that didn't seem to help, we very gently nudged her with a finger to see if that would allow her to move along - but her caught foot didn't budge. It appeared that the trapped portion of her foot could not currently fit back through the slits - the result of the strong swelling response present in aquatic snails. As fairly new snail parents, we hadn't expected that a healthy adult snail could have trouble with the millimeter-thick slit of the intake pipe. We began our increasingly frantic research.
Archived forum discussions revealed that this was a relatively common issue - more often seen with smaller snails, stronger filter flow, and larger intake slits. The tales were cautionary. Kindhearted, mourning snail owners shared mostly unhappy outcomes: left the snail alone, and he perished; tried to pull him out, and chunks of snail were left in the filter; tried to pull him out, and the snail sustained injury to his mantle. Gravely injured snails were seen floating in the tank or sitting at the bottom having retreated far into their shells - and typically perished a few days later. The grief and guilt of the writers was relatable.
With these stories in mind, we again tried in vain to gently (gently!) wiggle our friend free, and elected to let her be for the moment, filter off, and hope that she could escape overnight.
The solution:
Heather awoke around 3:30am and staggered over to check the aquarium. The mystery snail hadn't budged. Another gentle wiggle on the shell proved futile. Heather decided that the only solution was to somehow break the pipe. She decided to wait for morning and tackle the problem with better equipment in the light of day.
Inspection in the morning revealed that our snail was still stuck - and a trace of either tank detritus or snail excretion had accumulated under the slits. We wondered if it might be snail blood/hemolymph. Dan agreed to sacrifice the lily pipe.
We grabbed gloves, eye protection, and a metal file, then filled a small bowl with tank water. We chopped the tubing below the inflow pipe, then gently hoisted the pipe into the bowl, gently supporting the snail so as not to aggravate the foot. We carried the bowl to the table and began the slow process of filing away at the pipe. First we scored the glass near the bend of the pipe and snapped it so that we could access all around the inflow slits. Then, slowly, we filed away near the slit that held the largest section of foot. A newer, thin diamond-tipped file might have sped things up, but we had to use what was available. We took care to keep the snail submerged in the bowl of warm tank water near the surface, swapping her into a fresh bowl of tank water once the first one began to cool. She waved her tentacles around slowly after a few minutes, and then waited patiently - we imagine she understood that we were going to attempt a rescue.
After roughly 40 minutes of very careful filing we had cut a very deep groove around the pipe - but suddenly we noticed that her grip had changed. Somehow, the largest trapped chunk of her foot had become detached. Alarmed, we gently slid the smaller portions of foot free and returned her to the tank. The precise mechanism of injury is still unclear; we suspect that the connection to that section of foot had already been weakened - we recalled seeing what looked like trace amounts of dark blood near the slit - and suppose that the vibration of filing may have eventually caused that piece to break off. Perhaps a slip of the file had jolted her, and the edge of the glass slit had done the rest.
It was not the outcome we wanted. Our snail friend floated near the surface, operculum ajar. There were only small signs of life - a small movement of tentacle, a reflexive closing of the operculum when nudged. We assumed the worst. Since it was Christmas Eve, Dan worked to keep the day's plans somewhat intact and care for the horses. Having broken the filter inflow and with the clock ticking, Heather grimly went out to get a sponge filter to keep the tank's other inhabitants - a few guppies and a few otocinclus - in good health.
Upon her return, as we peered into the tank and prepared to install the new filter, our small snail friend suddenly plummeted down to the substrate and closed her operculum - she was still alive. We got the new filtration system set up, but figured she was unlikely to survive.
We were astonished to observe that throughout the day, our mystery snail not only persisted, but improved. She was staying in place, but in a few hours she was peeking out of her shell and actually eating the globs of Soilent Green we gingerly placed in front of her! Later she was scooting short distances - with some difficulty, given her injured foot.
We are currently roughly three days out from when she got stuck, and are thrilled to report that she has continued to eat with enthusiasm and made it across the tank today. She seems in good spirits, as best we can tell. She is still resting more than usual, but has been quite interested in the base of the new sponge filter. She lost approximately 1 cm^2, 1/5 in^2 of foot. The otocinclus were unexpectedly supportive, and sat very near her while she rested.
**Edited to add**
As of a little over two weeks post-incident, our snail friend seems to be in good health and has returned to normal activity. Following a brief encounter with her male snail friend she even laid a clutch of eggs! The damaged foot is still smaller than it was, but appears to have somewhat regenerated. A happy ending to this snail tale!