Monetaria moneta/annulus - Money Cowrie

Money Cowrie may refer to Monetaria moneta, Monetaria annulus or visually similar specimens from these closely related species. Both belong to the cowrie family Cypraeidae and originate from tropical Indo-Pacific marine environments.

The smooth, polished shell may be partly or completely covered by the living animal’s mantle. This mantle cleans the shell and produces the glossy surface characteristic of cowries.

Key features

• Small tropical marine cowrie
• Sold as Monetaria moneta or Monetaria annulus
• Common name: Money Cowrie
• Monetaria annulus is also known as Gold-ring Cowrie
• Smooth and highly polished shell
• Pale, yellowish or gold-ringed coloration
• Mantle may cover the complete shell
• Grazes microalgae and biofilm
• Consumes detritus
• Primarily nocturnal
• Peaceful
• Suitable for mature marine aquariums
• Useful as part of a varied clean-up crew
• Reef safe with caution
• May disturb soft corals when natural food is scarce
• May require supplemental algae foods
• Sensitive to copper-based medications
• Requires stable marine-water conditions
• Species, pattern and size may vary naturally

Care information

• Scientific identification: Monetaria moneta / Monetaria annulus
• Former names: Cypraea moneta / Cypraea annulus
• Family: Cypraeidae
• Adult size: approximately 2–4 cm
• Diet: microalgae, biofilm, detritus and supplemental algae foods
• Activity: primarily nocturnal
• Temperament: peaceful
• Reef compatibility: with caution
• Care level: easy to intermediate
• Origin: tropical Indo-Pacific
• Recommended minimum aquarium volume: approximately 40–60 litres

Suggested water conditions

• Temperature: approximately 24–28 °C
• Specific gravity: approximately 1.023–1.026
• pH: approximately 8.0–8.4
• Alkalinity: approximately 7–12 dKH
• Calcium: approximately 400–450 mg/l
• Magnesium: approximately 1,250–1,400 mg/l
• Ammonia: 0 mg/l
• Nitrite: 0 mg/l
• Flow: low to moderate

Feeding

Provide an established aquarium with mature live rock and natural biofilm. When natural algae become scarce, supplement with:

• Dried nori seaweed
• Marine algae sheets
• Spirulina-based sinking tablets
• Algae-based invertebrate foods
• Mature biofilm-covered rock

Offer supplemental food after the aquarium lights dim and remove uneaten food the following morning.

Introduction

1. Confirm that the aquarium is fully established.
2. Check that sufficient grazing surfaces are available.
3. Measure temperature and salinity.
4. Dim the aquarium lighting.
5. Equalise the transport-water temperature.
6. Acclimate slowly to salinity and water chemistry.
7. Never pull the cowrie from the transport container.
8. Transfer it underwater with its substrate or a small container.
9. Place it onto stable, biofilm-covered rock.
10. Confirm that the muscular foot attaches securely.
11. Observe activity after the aquarium lights switch off.
12. Supplement with algae food when the aquarium is exceptionally clean.
13. Avoid all copper-based medications.