Scalability and Flexibility always creates a problem when the task gets huge. The problem with maintaining a large aquarium is you don’t get the liberty of just flushing out all the water and cleaning everything. The problem definition is a bit difficult and complex. So the solution also has to be a bit different and un-orthodox.
A year back, I had got some new Amazon swords from a local shop and with them came some super tiny Ramshorn snails (max. adult size < 5 mm) and some super tiny black apple snail (max. adult size < 5 mm).
Initially I was happy, since they will add to my Algae cleaning crew. But very soon, I got disappointed since these snails multiplied exponentially. Being a Walstad setup, I could not risk using any chemical weapons against these snails.
Manually killing/removing, lesser feeding cycle, were the only options which did not give any appreciable results.
Accidentally a neighbour of mine gave me a 2-inch gold fish. Some friend of theirs was relocating out of town and therefore was giving out all their fishes. As per my understanding, Gold Fishes and Planted Aquarium don’t go well. Gold fish tend to eat away most of the plants. I could not deny my neighbour and since it was a tiny 2-inch Gold fish, I let it in.
My plants had grown up in jungle, so having a small gold fish should not create much of any issue.
Days went by and I was minutely watching the Gold fish behaviour and the plants. I did see the Gold Fish nibbling out here and there, but it seemed to be eating the decaying leaves/plant matter.
Almost a month went by and I suddenly realized that the snail population (ramshorn and tiny black apple snails) had dropped drastically. I was literally scratching my head trying to identify if there was some change in my Aquarium routine. But unfortunately no!! I had my same Aquarium routine.
I thought that possibly the Gold Fish must have something to do with it. But I never saw it aggressively getting after these snails. Even Google didn’t say anything about Gold fish eating snails. I was a bit skeptical about my inferences.
For some reason, I had to move this gold fish in my secondary tank which I used mainly was some miscellaneous stuff. It also had the snail problem and viola, around a month later there are almost no snails.
So Gold Fish is your ultimate weapon for controlling your unwanted snail population. But I still think Gold Fish do eat plants, possibly when there is not too much of food for him.
Note: My Orange Apple snails were un-harmed, possibly because they were too big for the gold fish to handle.