Breeding the Cerith Snail (Cerithium spp.)

Cerithium snails lay gelatinous egg strings, but the eggs hatch into long-lived planktonic veliger larvae. They reproduce readily yet cannot complete their cycle in a closed reef aquarium.

Overview

Cerithium is a genus of small to medium marine sea snails in the family Cerithiidae, the ceriths. They are elongated grazers and deposit feeders that work through sand and crevices on intertidal rocky shores and reef flats. In aquaria they are popular nano-reef cleanup animals that consume detritus, diatoms and leftover food.

Sexing

Ceriths have separate sexes and are not visibly sexually dimorphic. Keepers cannot distinguish males from females by shell shape or pattern, so spawning in a tank is opportunistic rather than something that can be deliberately paired.

Spawning & Larvae

Cerithium deposits pale-yellow egg masses as continuous, tightly folded strings, each capsule holding an egg in a gelatinous matrix, attached to algae or hard substrate. Free-swimming veligers hatch within several days and feed on diatoms and small plankton with the ciliated velum; the planktonic phase can last roughly 90 to 120 days before settlement.

Common Challenges

• The long planktonic phase, up to 90-120 days, far exceeds what a closed tank can support.
• Tiny veligers are removed by skimmers, filters and pump intakes.
• Larvae depend on a steady plankton food supply that home reefs lack.
• Even when eggs are laid in the display, settlement and metamorphosis almost never occur.