Controlling Pest Snails in Aquariums
Bladder, ramshorn and Malaysian trumpet snails multiply rapidly when overfed. Populations are reduced by feeding less, trapping, manual removal and assassin snails.
Identification
The common aquarium pest snails are the bladder snail (Physella acuta), ramshorn snails (family Planorbidae) and the Malaysian trumpet snail (Melanoides tuberculata). Bladder snails are small air-breathing pulmonates with a pointed, sinistral shell. Ramshorn snails have a flat, planispiral coiled shell and often a reddish body from iron-based hemoglobin in their blood. Malaysian trumpet snails have an elongated cone-shaped shell and burrow in the substrate, being most active at night.
Why they multiply
These snails feed on algae and detritus and reproduce very quickly. Physella acuta is a self-compatible hermaphrodite that can lay 50-100 eggs per week, and Melanoides tuberculata reproduces by parthenogenesis and bears live young. A single hitchhiker on a plant or decoration can establish a population. Excess reproduction usually results from an oversupply of food when fish and shrimp are overfed.
Are they harmful
Pest snails are not parasitic and do not generally harm fish; many aquarists value them as algae eaters and substrate cleaners. The objection is aesthetic and the difficulty of controlling large numbers once established.
How to remove them
- Feed less: snails reproduce only with enough food, so feed only what fish eat within a few minutes.
- Remove food sources by pruning plants, scrubbing algae and gravel-vacuuming organic debris.
- Manually pick snails out with tweezers or by hand whenever you see them.
- Use a snail trap baited with vegetables or fish food to collect them.
- Add assassin snails (Anentome helena), which are carnivorous and prey on other snails.
Prevention
- Quarantine and rinse new plants and hardscape.
- Avoid overfeeding and remove uneaten food.
- Keep the substrate and decor clean of excess organic matter.
- Keep the population in check rather than letting it explode.