At a glance the quick version
Shell length. Wikipedia says large specimens rarely exceed 20 cm; SeaLifeBase gives a common size of 25 cm and a maximum of 41.7 cm.
Looks how to spot one
Heavy ridged shell with a fleshy, coloured mantle
A clam with a thick, scalloped shell that often sits partly buried in rock. When open it spreads a velvety mantle over the edge of the shell, patterned in vivid blue, green, gold or brown.12
Personality what they are like
Completely peaceful. It may shift position at first, then settles and should be left where it chooses to attach.3
Daily activity how busy a day looks
Sessile once settled; it opens and closes its shell and mantle with the light.3
Grooming and care the hands-on bits
Give it very strong lighting and stable reef water. Clams over about 5 cm usually need no extra feeding. Avoid tankmates that pick at clam mantles.3
Home where they are happiest
A mature reef tank with intense light and low to medium flow, placed on rock or sand high enough to get plenty of light. In the wild it lives on sunny reef flats and lagoons at about 0-35 m and 23-30 C.23
Food basics what goes in the bowl
Most of its food comes from zooxanthellae, algae living in its mantle that turn light into sugars. It also filters phytoplankton and takes up dissolved nutrients.123
Company who they like around
Lives alone and does not need company; it is peaceful toward all tankmates.3
The story where it all began
Peter Friedrich Röding described the species in 1798. It is the most widespread giant clam, and its bright mantle and modest size made it a favourite reef-aquarium clam; many in the trade are now farm raised.13
Fun facts for the dinner table
- 1
It starts life as a male and becomes a hermaphrodite at about 15 cm long.1
- 2
Spawning is cued by the moon, the time of day and eggs or sperm from nearby clams.1
- 3
Shiny reflective cells in the mantle may shield it from strong sun or help its algae.1
- 4
It is called the small giant clam because it looks like the huge giant clam but stays far smaller.1
Recognised by the official bits
- Taxonomy (via Wikipedia)
- First described by Röding in 1798 (as Tridachnes maxima); a giant clam in the family Cardiidae.1
- CITES
- Listed on Appendix II, so international trade needs permits.1
- IUCN Red List (via SeaLifeBase)
- Least Concern.2
The care rhythm a typical week and year
A typical home-care rhythm for a Maxima Clam. A starting point, not a vet's advice.
- FeedingDepends on species, many feed from the light and the watervaries
- Salinity checkevery week
- Water testevery week
- Top-upTop up evaporation with fresh RO water, not salt waterevery day
- Water changeAbout 10 to 20% of the waterevery 2 weeks
- Light checkevery month
Owner questions the things everyone asks
How often should I feed my Maxima Clam?
For clams over about 5 cm, no extra feeding is needed as they get most of their food from the light and water. Smaller clams may need phytoplankton supplements; check with a vet for guidance. Furry Diary's starting plan suggests feeding depends on the species.3 Pet Wiki plan
What does a Maxima Clam eat, and what should it never eat?
Your Maxima Clam gets most of its food from algae living in its mantle (zooxanthellae) and also filters phytoplankton from the water. It also takes up dissolved nutrients. Avoid any food that could pollute the water; ask a vet for specific supplements.123
How much space does a Maxima Clam need?
It needs a mature reef tank with intense light and low to medium flow, placed on rock or sand high enough to get plenty of light. The exact tank size varies; ask a good breeder or vet for recommendations.23
What temperature, light or water does a Maxima Clam need?
It needs very strong lighting and stable reef water with a temperature between 23-30°C. Keep water quality high with regular testing and water changes as per Furry Diary's plan.23 Pet Wiki plan
How often should I clean a Maxima Clam's home?
Clean the tank as part of regular maintenance: top up evaporation daily with fresh RO water, test water weekly, and change 10-20% of the water every two weeks. Avoid disturbing the clam once it settles. Pet Wiki plan
Can a Maxima Clam live with others?
Yes, it can live with other peaceful tankmates, but avoid fish or invertebrates that might pick at its mantle. It is peaceful and does not need company.3
How long does a Maxima Clam live?
Lifespan varies; ask a good breeder or exotic-pet vet for specific information.
Can I handle a Maxima Clam?
It is best not to handle your Maxima Clam; once it settles, leave it in place. Handling can stress the clam and damage its delicate mantle.3
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.
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Crocea ClamWhere this comes from
Every fact on this page has a numbered source. Spotted an error? [email protected].
- Tridacna maxima (Wikipedia) en.wikipedia.orgused for names, range, size, mantle, nutrition, reproduction, CITES, history
- Tridacna maxima (SeaLifeBase) sealifebase.seused for maximum size, depth, temperature, range, IUCN status
- Maxima Clam (Saltwaterfish.com) saltwaterfish.comused for aquarium care, lighting, flow, placement, feeding
- Clams category (Saltwaterfish.com) saltwaterfish.comused for mantle colour forms offered
Checked 2026-09-30. Text is written in our own words from these sources.