Nassarius Snail

The Fluctosus Nassarius is a commercial name used in the marine aquarium trade to designate a group of Extra Large (XLG) Nassarius Snails originating from the Indo-Pacific. While this name is not a valid scientific classification, the snails sold under this label are typically robust, highly efficient scavengers, usually belonging to species like Nassarius distortus, Nassarius margaritifer, or similar large Nassarius sp. members.

These larger snails are prized for their ability to manage waste in medium to large aquariums. They can grow up to 2 inches (5 cm) in length, making them significantly bigger than the smaller Caribbean species ( Nassarius vibex ). They possess the genus's characteristic long, tube-like siphon, which they use to "smell" food in the water column while remaining hidden beneath the substrate.

The Fluctosus Nassarius spends almost all of its time buried in the sand bed, emerging only when food is introduced—a dramatic surfacing known as the "zombie snail" effect. This constant movement and burrowing action is critical for aerating the sand and preventing the buildup of anaerobic pockets, which can release toxic gases into the tank water.

Diet & Aquarium Role:

• Diet: The XLG Nassarius Snail is an Obligate Scavenger and Carrion/Detritus Eater. Its diet consists exclusively of decaying organic matter, detritus, fish waste, and uneaten meaty foods that settle on or within the substrate. They are not known to consume nuisance algae.
• Aquarium Role: Their core function is sand-sifting and aeration. Their larger size and strength make them particularly effective at turning over the sand in deeper beds (3 inches or more) and consuming larger pieces of discarded food that smaller snails cannot manage as quickly.
• Feeding: While they will scavenge, in a clean, established tank, they should be supplemented with sinking meaty foods (pellets, small pieces of frozen shrimp or clam) placed on the sand bed to ensure they receive adequate nutrition. They will rush to consume any dead or dying tank inhabitants.
• Reef Compatibility: The Fluctosus Nassarius is Completely Reef Safe. They are peaceful, pose no threat to corals or healthy fish, and are one of the most beneficial invertebrates for maintaining substrate health. They should be protected from known snail predators like Puffers, Triggerfish, and larger Wrasse species.
• Temperament: Peaceful Scavenger.

Quick Facts

• Scientific Name: Commercial name; typically a large Indo-Pacific species like Nassarius distortus
• Primary Common Name: Fluctosus Nassarius
• Other Common Names: XLG Nassarius Snail, Super Tongan Nassarius Snail
• Origin: Indo-Pacific
• Max Size: 1–2 inches (2.5–5 cm)
• Temperament: Peaceful Scavenger
• Diet: Carrion/Detritus (Sifts sand for meaty leftovers)
• Minimum Tank Size: 20+ Gallons (Requires a sand substrate)
• Reef Compatibility: Safe