While I was in town not long ago, I got a message from my daughter, informing me of both a surprise, and a mystery.

We have snails in our fish tank.

We have no idea where they came from.

Our initial reaction was, Oh, no!!! But as you can see from the photo, we also have an algae problem, and the snails are very enthusiastically cleaning our aquarium glass for us.

We’ve had problems with snails with past aquariums, which is why we had our “oh, no” reaction, but these snails look different from those. In fact, they look a fair bit like our pond snails.

It’s possible they got a ride into our tank on the plants I bought last month. Unlikely, but if not that, then they would have had to get in through our well water. Which is even more unlikely.

The last time we had snails show up in our tank, it wasn’t a mystery. The tank we had at the time was a 20 gallon tower style tank. We had some fake plants, a few small fish, and a pleco. I picked up a couple of golden apple snails. As I was adding our new acquisitions to the tank, I noticed a tiny snail had hitched a ride on one of the golden apple snails. It had a dark shell, and the shop I bought them at did have a dark shelled snail (“mystery snails”, I believe they were called) that were the same size and shape as the golden apple snails, so I didn’t think much of it.

Well, it turned out they were a completely different kind of snail. They stayed very small in size, and were very prolific.

Before we knew it, we had an infestation. It was so bad, I was even scooping them up with a net and throwing them out. Finally, out of desperation, we took our fish and golden apple snails out, emptied the tank and disinfected all the decorations. I also replaced the gravel completely. The tank itself was also scoured and disinfected.

We kept a close eye on the tank for some time, and I was sure we had won the battle.

I was wrong.

Somehow, some eggs had managed to survive the cleaning. First, a few tiny snails showed up. Little black specks of them. Before we knew it, despite all our efforts, our tank was once again infested.

I went to the shop we had bought the snails from and talked to the staff about it. Some of their own tanks had also become infested, I learned, and they had some major issues because of it. I got some advice on a product that we could try to use that would kill invertebrates, but would leave the fish unharmed. They did not sell it, though, and only bought it themselves, in bulk, to treat their own tanks.

Meanwhile, our own tank had thousands of the little buggers, even though I was trying to scoop as many out as I could. The glass on the tank was so covered with them, it was hard to see in! The blue of the gravel was hidden by the black of hundreds of shells.

Then one morning, I came down stairs, walked past the tank, then stopped to do a double take.

The tank was clear.

Our fish were still there. So were the apple snails. But the nuisance snails were gone, without a trace. Not even a discarded shell, anywhere.

It was so dramatically different, it was surreal. What happened? Where did they go?

They never returned, either.

To this day, we don’t know what actually happened. How did thousands of snails disappear without a trace, overnight?

We do have one theory.

Our pleco.

We think he might have discovered he had a taste for them, and ate them like popcorn!

We had had two plecos. We named them Boris and Alistair. Then Boris ate Alistair, and we never got another one. So we knew he had a taste for things other than his algae pellets. Later, we discovered him trying to eat the apple snails and it was rather horrifying, so we never got snails again after those were gone.

In time, Boris got really big. He’s partly why we went from a 20 gallon tank to a 300 gallon tank. By the time he died, he was about 18 inches long!

We don’t have a pleco right now. We do have an algae eater, but he doesn’t eat the green algae that’s growing on the glass.

I wonder if it’s time to get another pleco?

The Re-Farmer