for the week of 3/12/98

Just about everyone who has kept an aquarium has had to deal with a snail infestation at one time or another – and knows how irritating it can be trying to get rid of the little critters. While snails are not directly harmful to fish, a huge population of them can be unsightly and cause the aquarium to be overcrowded – and making huge populations seems to be exactly the sort of thing that most snails are good at! Many aquarists, after turning on the lights early one morning and seeing a tank swarming with snails, have only two questions on their minds: where do they come from and can we get rid of them once and for all?

Although it may seem to be the case, snails do not simply appear in an aquarium out of nowhere. They, or their eggs, are unwittingly added to one body of water from another body of water, most commonly on live plants, but possibly on a net, ornament, or rock, or even in a bag of fish. Snails lay adhesive eggs on just about any surface inside the aquarium including plants, (both live and plastic) rocks, driftwood, ceramic ornaments, gravel, or even on the glass itself. It is possible, then to prevent infestation by closely inspecting all items before adding to the aquarium.

An additional method of prevention is to use a “dip” (e.g. Lime-It by Aquatronics) to kill snails and their eggs before new items are placed into the aquarium. These can not be used in an existing aquarium stocked with fish, but must be placed in a separate container and mixed with water. Any item which you wish to put in the tank is then dipped into this liquid, killing most of the snails or eggs.

Once snails have populated a tank, eradicating them can be an exercise in frustration. Some people have gone through the trouble of boiling the gravel, decorations and filters only to have the snails rear their little heads again only a few weeks later. Others spend hours trying to pick out every last snail, but find the population exploding again in no time.

One of the earliest products for killing snails was a copper sulfate treatment which if kept in the aquarium at the right concentration was fairly effective. The problem with this medication is that it had to be kept at a concentration high enough to kill the snails but not too high as it would kill the fish and plants. Failures and disasters were rather common occurrences, and these medications are no longer available.

Baits, such as carrots, lettuce and zucchini and fish food pellets may be used to remove snails. A small slice is placed on a plate or directly on the gravel at night, and the lights are turned off. After a few hours the bait, and hopefully a horde of feasting snails, is netted out of the tank. The bait is replaced every night until no more snails are collected. This method is not the most efficient but sure beats picking up snails by hand one-by-one.

One of the most effective removal methods is to get fish that eat the snails. The clown loach is the number one choice for eating snails. It is a scavenger by nature but has a sweet tooth for snails. They can be purchased small (usually about an inch or two) and will eat any snail it can fit into it’s mouth. They also can grow quite large (8″ and up) and they will clean up the adult snails also. Clown loaches are also peaceful and will not harm other fish in the aquarium. Puffers, leporinus and some of the fish in the Botia family are also great at eating small snails but may only be kept with more aggressive tankmates.

“Tip of the week” appeared regularly in 1999 and 2000.