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Mollusk Care Sheet

Developed with and approved by a qualified veterinarian.

This care sheet includes a variety of mollusks, including:

  • Flame scallop
  • Electric flame scallop
  • Tiger conch
  • Fighting conch
  • Spider conch


Lima scabra, Lima sp., Strombus sp. Strombus alatus, Lambis lambis.

Scallops are marine bivalves whose bodies are enclosed in two shells; they are related to oysters. Most scallops can propel themselves over the ocean floor, although some burrow into the sand or use their byssal filaments to secure themselves to a solid surface. Flame scallops are filter feeders and are recommended for experienced marine aquarists. Most conchs help aerate the sand bed and remove algae and detritus from the aquarium.

Table of Contents

Typical appearance and behavior

  • Some scallop species prefer to attach to a solid surface, while others prefer to sit in the substrate
  • Flame scallops can be kept singly or with other bivalves
  • Scallops have a 100+ tiny eyes lining their outer edge or mantle
  • Bivalves are nature’s version of water filters
  • Mollusks are invertebrates, like squids, slugs and clams
  • Most conchs grow too large for the home aquarium, but a few species, like the fighting conch, can be a good addition to a cleanup crew


Care difficulty Beginner to advanced, depending on species
Average Life Span Depends on species
Average adult size Depends on species
Diet Omnivore, detritivore or filter feeder, depending on species
Minimum habitat size 10+ gallons, depending on species
Water temperature 74–80°F
Specific gravity 1.023–1.025


Habitat size

A minimum of 10+ gallons is recommended for mollusks; however, water conditions can change rapidly in smaller water volumes, and a larger aquarium is recommended for larger mollusk species.

Building your habitat

  • Water health -
    • Provide proper filtration to ensure optimal water quality to help maintain health; depending on species, slow to strong water circulation will mimic water currents found in the mollusk's natural habitat
    • Stable water quality (pH, ammonia, nitrate, nitrite) and water temperature are critical to the health of aquatic life
    • If you are unsure of your water quality, bring a sample to Petco for free testing
    • A protein skimmer can help maintain great water quality and high dissolved oxygen levels
    • An aquatic heater should be used to stabilize water temperature, ensuring it does not fluctuate more than +/-2 degrees in a 24-hour period
    • The specific gravity should remain stable; do not allow specific gravity to fluctuate more than +/-0.001 in a 24-hour period
  • Décor - Provide rock and décor for hiding places and plenty of room for movement
  • Substrate - Conchs will need a deep sand bed to burrow into and scavenge for food
  • Live rock can provide a natural food source while also enhancing biological filtration

What do mollusks eat?

A well-balanced mollusk diet depends on species:

  • Flame scallops: Eat live, floating microplankton and need supplements of phytoplankton and liquid foods
  • Conchs: Usually eat algae, leftover food and detritus (decayed matter) in the aquarium

Things to remember when feeding your mollusk:

  • Flame scallops: Feed supplements to each scallop individually by dispensing food near the mouth with a pipette or straw

Mollusk care

  • Maintaining great water quality with regular water changes and adequate filtration is important to help keep your mollusk healthy
    • Daily: Check filter, water temperature, specific gravity and other equipment
    • Weekly: Check water quality at least once a week.
    • Monthly: Change 10–25% of the total volume of water every 2–4 weeks, or as needed; change filter media monthly
  • Copper-based medications are toxic to marine clams
  • Mollusks are sensitive to high levels of nitrate
  • Shelled mollusks require calcium carbonate to build their shells; be sure to provide proper calcium levels
  • Avoid overcrowded conditions, which are a major cause of stress and disease

Where to buy aquarium mollusks

Mollusks are available for purchase at your local Petco Pet Care Center location; availability varies by location. Please call ahead to check availability.


Tank mates

Reef-safe species make good tank mates, such as:

  • Basslets
  • Blennies
  • Chromis
  • Clownfish
  • Dartfish
  • Dottybacks
  • Dragonets
  • Gobies
  • Jawfish
  • Reef-safe wrasses
  • Tangs

Introduce new inhabitants to the aquarium gradually.


Signs of a healthy mollusk

  • A flame scallop’s mantle should be expanded and breathing siphons extended; its shell should close quickly when bothered or reacting to lighting
  • Flame scallops should have deep red coloration
  • Conchs should emerge from substrate when food is added to the aquarium

Red flags (if you notice any of these signs, contact your local aquatic specialist or aquatic veterinarian)

  • Flame scallop mantle falls inward, away from shell; shell fails to close quickly when bothered
  • Flame scallop loses color
  • Flame scallop has gaping mouth
  • Conch doesn’t emerge from substrate when food is offered

Common health issues

Little is known about diseases that affect mollusks; as long as environmental conditions and food supplies are adequate, mollusks are fairly resistant to disease.


  • What are mollusks? Mollusks are invertebrates without backbones, such as snails, clams, nudibranchs and scallops.
  • What do mollusks eat? A mollusk’s diet depends on their species and can range from algae to leftover food and detritus.

Additional care sheets

Notes and resources

Ask a Pet Care Center associate about Petco's selection of products available for the care and happiness of your new pet. All products carry a 100% money-back guarantee.

Because all aquatic life are potential carriers of infectious diseases, such as atypical mycobacterium and salmonella, always wash your hands before and after handling your aquatic life or habitat contents to help prevent the potential spread of disease.

Pregnant women, children under the age of 5, senior citizens and people with weakened immune systems should contact their physician before purchasing or caring for aquatic life and should consider not having aquatic life as a pet.

Go to the Centers for Disease Control at for more information about aquatic life and disease.

The information on this care sheet is not a substitute for veterinary care. If you need additional information, please contact your veterinarian as appropriate.