Maxima Clam : Tridacna maxima

Phylum:  Class: Order: Family: Subfamily Genus: Species:
Mollusca Bivalvia Venerioda Cardiidae Tridacninae Tridacna T. maxima

Common Names:  Maxima Clam

Scientific Name:  Tridacna maxima

T. maxima exhibit a wide range of colors and patterns in their mantles.  Main color is frequently shades of blue, green, gray, brown, purple or yellow with blue being the most common.  The background color usually has blotches or stripped pattern in a contrasting color.  The shell is elongated with scutes.  The scutes are frequently absent on the bottom part of the shell where they have been worn off where they have embedded themselves into the substrate. Captive raises specimens will not show this same wear.

The incurrent siphon has small tentacles.  The mantle sometimes has protuberances, usually only along the edge.  Maximum size is approximately 14″ in the wild, though in captivity, 6-7″ is a large specimen  T. maxima is easily confused with T. crocea when looking at the mantle.  The shell is a better way of  differentiating between the two types of clams.  As you can see in the pictures below, the shell has heavy fluting or waviness of the edge of shell and it has prominent scutes which are the ridges extending out from the shell along the sides.  The Crocea has a much smoother shell.

Natural Environment:
Indo-Pacific in reef top, shallow water, high current areas where they embed themselves  partially into the substrate (rock or coral) attached by their strong byssus filaments.  Typically on the very edge of the shell is visible with only minimal mantle expansion.    

T. maxima is a moderately hardy clam which usually does well in reef tanks given strong lighting and clear water conditions with low to moderate water flow.

T. maxima is a light loving clam and requires fairly intense lighting, preferably metal halide or high intensity LED.  High intensity T-5 can also work if the clams are located fairly close to the lights.  The clam coloration can change somewhat depending upon lighting conditions it is kept under.

Water Current:
In the wild, Maxima clams inhabit moderate to high current locations in the reef crest.  In the aquarium, because the water flow tends to be more laminar and their mantel extension tends to be greater, Maxima clams seem to prefer a more moderate water flow.

None.  Need to keep it away from aggressive neighbors.

Primarily photosynthetic.  They may benefit from feedings of phytoplankton, but it is not required.  Very young clams under about 1″ in size seem to depend on feeding more than older clams, so it is best to avoid the very small specimens which have a poorer survival rate than the larger clams.

Supplements & Water Chemistry:
Salinity should be maintained between sg 1.024 and 1.026.
Alkalinity should be maintained in the dKH 7-12 range
Calcium should be maintained at 400 ppm or higher.
pH should be maintained between 8.1-8.4.  Lower at night down to 7.9 is OK.

Does well within a range of at least 74º to 84º F.  77º to 80º F is ideal.

Tank Positioning:
Position these clams on the substrate in the bottom of the tank in a low to moderate water flow area.  The can also be positioned up on live rock if care is taken to locate it so that it cannot move and fall from its perch.  Clams have a foot that they can extend out of the shell and use to re-position themselves if they are not happy where you put them initially.  If placed on a solid surface, once settled in they attach themselves permanently using byssus threads. This makes them difficult to near impossible to re-position without risking damage to the clams when place on large pieces of liverock.  That is one benefit of keeping them on a soft substrate where they cannot attach or placed on a small rock where the clam and rock can be moved together if needed.  You also want to keep the Maxima fairly low in the tank for viewing since the colors of the mantle can look dramatically different and more colorful when view from the top than the side, so in general you want to position the clams so that you are able to look down at them from a steep angle.  That position of course depends on the tank having strong enough lighting to reach the bottom of the tank.

Maxima clams in the hobby are predominantly farm raised now.  This farming is only done where the clams live naturally and is not practical for the home propagator to attempt.

All photos by ReefCorner © All Rights Reserved