Maxima Clam (Tridacna maxima): Ultimate Care Guide

Looking for a splash of iridescent color in your reef aquarium? Maxima Clams can be finicky to care for, but reward the attentive hobbyist with great colors and long lifespans. Native to waters in the Indo-Pacific region, this bivalve mollusk can grow to 12 inches in captivity and may live for decades. Many colors are available so you can choose the variety which best matches your tank’s aesthetics. In this guide we’ll explore everything needed to get years of enjoyment from this colorful clam species!

Maxima Clam Care

Maxima Clams need larger tanks and bright lighting for best health and longevity. Smaller specimens may need frequent feeding with phytoplankton substitutes. Larger Maximas are often content with feeding through photosynthesis of zooxanthellae which live in their mantles. This species does best in mature aquariums with healthy populations of phytoplankton and other microfauna.

Are Maxima Clam easy to care for?

Maxima Clams can be a challenge to care for successfully. Between their need for stable water chemistry and special lighting needs they are best kept by more experienced hobbyists.

Maxima Clam (Tridacna maxima)
Maxima Clam (Tridacna maxima)

Maxima Clam Placement

Maxima Clams need intense lighting, but must be acclimatized to the light in a new tank environment. At first, they should be placed on aquarium substrate or live rock with their mantles facing upward. Placing newly received Maxima Clams in lower, and dimmer tank areas lets them become accustomed to the light in their new environment. Eventually you can move them higher where they can receive brighter light. It’s important to remember this species receives nutrients via zooxanthellae which live in their mantles and need light to properly photosynthesize. Lighting type and intensity will dictate where Maxima Clams should be placed in your aquarium. Note that aqua-cultured specimens can live on substrate but wild caught Maxima Clams should always be placed on live rock. When placing a new Maxima, it’s best to cover the lower 1/3 to ½  with sand to prevent pests from entering their byssal opening.

Acclimating Maxima Clams

Maxima Clams are sensitive to rapid water chemistry changes and should be slowly acclimatized to a new tank’s water chemistry. A drip acclimator is often the best solution for gradually introducing water from your destination aquarium to an intermediate container. A type of adjustable siphon, drip acclimators let you control how fast your new clam is introduced to tank water. To use, place your clam in a bucket below the tank. Follow your drip acclimator’s instructions to start the siphon action and adjust drip rate. Usually, 2 to 3 drips per second is enough to introduce your clam to new water chemistry without shocking them with a rapid change.

Acclimating to water chemistry is important but so is lighting intensity. Maxima Clams do best under bright lighting. But in a new aquarium they shouldn’t be exposed to the brightest light immediately. Because every lighting setup is different, it’s impossible to give a timetable which works for every situation. In general, hobbyists who use high output lighting should give Maxima clams extra time in dimmer tank areas before moving them to brighter areas.

Maxima Clam (Tridacna maxima)
Maxima Clam (Tridacna maxima)

Temperature for Maxima Clam

Maxima Clam have a wide tolerance for water temperatures which should be between 74° and 83° F.

Lighting for Maxima Clam

Maxima Clams need exposure to high intensity lighting but there are some times where lower light is better. How can you tell how much light to provide? Examine your Maxima Clam’s mantle: if it’s iridescent this means their zooxanthellae population is healthy and ready for brighter light. Alternatively, a brown mantle is often a sign you should keep this species in dimmer light until they acclimatize to their new tank environment. Brown mantles are often seen on new aquarium additions where the stress of transport has caused the Maxima’s population of zooxanthellae to die back.

Water pH for Maxima Clam

Maxima Clams will tolerate a range of water pH between 8.1 and 8.4. This species doesn’t appreciate rapid water parameter changes, so avoid anything which would cause rapid alkalinity shifts.

Maxima Clam Size

Maxima Clams become sexually mature when reaching 3 inches. They are slow growers and can take 50 to 60 years to reach their maximum size between 12 and 14 inches.

Food & Diet for Maxima Clam

Maxima Clams mainly feed through photosynthesis of zooxanthellae which live in their mantles. They are also filter feeders that can consume phytoplankton and zooplankton from surrounding water. This species does best in mature aquariums with healthy populations of microfauna. Depending on a particular tank’s maturity it may be necessary to provide additional food such as marine snow or other phytoplankton substitutes. Smaller specimens up to 2 inches should be fed daily. Once the clam reaches 4 inches, feeding should happen a few times a week. When fully grown they can be fed weekly but it’s best to let mature Maxima Clams feed through photosynthesis and filter feeding from surrounding microfauna.

Maxima Clam Lifespan

Maxima Clams can live decades in captivity, but can live up to 200 years in the wild.

Maxima Clam Tank Size

Maxima Clams do best in larger aquariums. At least 100 gallons is recommended. Small tanks can have rapid water quality variations that can harm this species.

Maxima Clam (Tridacna maxima)
Maxima Clam (Tridacna maxima)

Maxima Clam Tank Setup

Mature reef aquariums with live rock provides the best environment for Maxima Clams. This species will eventually bore into and attach to live rock if available. It’s important to provide a mature tank with healthy populations of microfauna. While these clams can be fed with phytoplankton substitutes such as reef snow, live food is best. Adequate live phytoplankton is the main reason this species should only be placed in mature aquariums.

Bright lighting is critical for Maxima Clams. In nature they live in shallow waters with lots of sun exposure. Metal halide or bright LED lighting is best. If kept under fluorescent lights, this clam will need to be placed near the surface as close to light as possible.

Avoid any source of strong current such as wavemakers or the output of powerheads. Maxima Clams need some water flow, but strong currents can make them close up. If currents stay high for long periods it can interfere with feeding.

Breeding Maxima Clam

It’s possible to breed Maxima Clams in a home aquarium, but it isn’t easy. Captive breeding of this species is best left to professional breeders and advanced hobbyists. All Maxima Clams are born male and change to female. They breed by releasing eggs and sperm, usually around sunset. The eggs develop into larva which are at first free swimming. Eventually, the young change into a more recognizable clam form and settle into limestone substrate, coral rubble, or even live coral.

Common Problems with Maxima Clams

Maxima Clams can be afflicted by various things including snails, parasites, and environmental hazards. Snails are a common predator which can attack through the Maxima’s large byssal opening. Inspect your clam often for pyramidellid snails, and their clear egg sacs which can be hard to spot. Remove snails and eggs with a stiff brush. For serious infestations you might need to remove your clam from water for 15 minutes or more to allow the shells to dry and aid snail removal.

Snails pose a danger to Maxima Clams, but parasites are also a concern. A tell-tale symptom of parasite infestation is receding mantle, where the clam’s mantle pulls back from the edges of their opening. This is a serious problem and often results in death.

Maxima Clams are a demanding species and can die without correct water chemistry. If you see your clam opening widely this might be a condition known as gaping. Gaping can be the result of low nitrates in aquarium water. Test your water chemistry and take steps to correct it if needed.

Tank Mates for Maxima Clams

Maxima Clams is easy to pair with any species which isn’t prone to nipping, or is a known pest. Hermit crabs are a bad match. Additionally, Angels are a bad pairing because they are known to nip at clams. Wrasses can be a good match as they eat many common clam pests. Avoid placing clams near corals which have stinging tentacles or close to anemones.

Where can I find Maxima Clam for sale?

Maxima Clam are available from online sources and local fish stores. Expect to pay between $60 USD and $150 USD each, depending on size. This clam is available both live caught and aquacultured. Some hobbyists report that aquacultured Maxima Clams are easier to raise in an aquarium.

Maxima Clam Types

Maxima Clams are available in a wide variety of sizes and colors. These types are graded for sale to aquarium hobbyists. Some colors are more rare and desirable which can lead to price differences between different individuals in the same species. Let’s take a look at a few of the colors you’re likely to see when buying your own Maxima Clam.

Blue Maxima Clam

The most common variety, the Blue Maxima Clam is usually the most affordable Maxima available to hobbyists. This variety is easy to get from online sources and local fish suppliers.

Gold Maxima Clam

With striking gold mantles, Gold Maxima Clams are an unusual and colorful addition to reef aquariums. They range from having solid gold mantles to smaller amounts of gold woven into their iridescent mantle pattern.

Ultra Maxima Clam

A sought after grade of Blue Maxima, the Ultra Maxima Clam has especially striking turquoise blue mantle coloration. This is a great variety which can add a shock of bright blue to your reef tank!

ORA® Maxima Clam

Not a specific variety or color, ORA® Maxima Clams are aquacultured by Oceans, Reefs & Aquariums (ORA®) and can provide an easy way to get started with Maxima Clams. Compared to live caught specimens, ORA® aquacultured clams can be easier to keep in captivity.