[amcarrig]

tridacnid Identification Guide


T. Maxima



Mantle Color/Characteristics
Blue, purple, gray, brown, and yellow are common. Black specimens exist but are somewhat rare. Spotted, striped, or blotched. Patches of solid color are more common than multi-colored patterns.

Shell
Asymmetrical. 5 very distinct ribs. Moderately defined, tightly spaced scutes.

Approx. Adult Size
16"

Byssal
Medium to large byssal opening.Semi-rock boring.

Siphon
Small, simple tentacles on inhalant.

Lighting Requirement
Intense.

Placement
Preferably on rockwork. Brightly colored specimens require brighter lighting than brown ones. Brown T. maximas should be placed lower in the aquarium to prevent them from getting shocked by strong lighting.

Feeding
Phytoplankton only when clam is 3" or smaller. Light and supplemental phyto when larger.


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T. Crocea



Mantle Color/Characteristics
Blue, purple, yellow, green, gold, orange, and brown. Lines, spots, or blotches of yellow, blue, and green can also be seen.

Shell
Asymmetrical5 to 6 moderately defined ribs. Scutes are tightly spaced but not well defined.

Approx. Adult Size
6"

Byssal
Large byssal opening. Rock boring.

Siphon
Small, simple tentacles on inhalant.

Lighting Requirement
Intense.

Placement
Preferably on rockwork. Clams with bright coloring (especially blue) should be placed high in the aquarium.

Feeding
Phytoplankton only when clam is 3" or smaller. Light and supplemental phyto when larger.



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T. Derasa



Mantle Color/Characteristics
Wavy striped patterns or spots. Can be found in black, white, blue, yellow, and orange color combinations, but most mantles have a golden color. Some have bright green or blue lines.

Shell
Symmetrical. . 5 to 7 moderately defined ribs that lack scutes.

Approx. Adult Size
20"

Byssal
Narrow/small byssal opening.

Siphon
Large complex tentacles on inhalant.

Lighting Requirement
Strong.

Placement
On rockwork or on sand.

Feeding
Phytoplankton only when clam is 3" or smaller. Light and supplemental phyto when larger.



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T. Squamosa



Mantle Color/Characteristics
Beige, brown, or gold. Some can have blue or green blotches and some have stripes running parallel to the shell.

Shell
Symmetrical4-5 large, very defined ribs. Large, sharply defined, widely spaced scutes.

Approx. Adult Size
16"

Byssal
Medium to non-existent byssal opening.

Siphon
Large complex tentacles on inhalant.

Lighting Requirement
Strong.

Placement
On rockwork or on sand

Feeding
Phytoplankton only when clam is 3" or smaller. Light and supplemental phyto when larger.




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T. Gigas



Mantle Color/Characteristics
Blue, green, golden-brown, or yellow in color. Iridescent spots may also be present, especially near the edge of the mantle.

Shell
Asymmetrical4 to 5 defined ribs. Juveniles have some scutes on their shells but adults do not.

Approx. Adult Size
Up to 4'

Byssal
Small to nonexistent byssal opening.

Siphon
No tentacles on inhalant.

Lighting Requirement
Strong.

Placement
On sand.

Feeding
Phytoplankton only when clam is 3" or smaller. Light and supplemental phyto when larger.




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T. hippopus



Mantle Color/Characteristics
Brown-green with some deep yellow striping. The mantle of H. hippopus does not extend past the shell edge as do the other tridacnids.

Shell
Asymmetrical and very distinct.Typically has 7 to 8 well defined ribs which lack scutes.

Approx. Adult Size
14"

Byssal
Small byssal opening.

Siphon
No tentacles in inhalant.

Lighting Requirement
Strong.

Placement
On sand.

Feeding
Phytoplankton only when clam is 3" or smaller. Light and supplemental phyto when larger.










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