|Latin name||Tridacna derasa|
|Local name||Derasa Clam|
|Family||Tridacninae - Tridacna|
|Origin||East Indian Ocean, Australia, Indonesia, Central/West Pacific|
|Max length||60 cm (23,6")|
|Minimum volume||200 cm (53 gal)|
|Suitable for aquarium||Suitable with care|
|Reef safe||Always reef safe|
This species can be bred in captivity, one can therefore consider asking your local fish store for a captive bred specimen.
This Tridacna is one of the most hardy and larger types, and will become quite large under the right circumstances.
They can be identified by the 6-7 vertical folds on their shells.
Derasa clams do not stick as well as the other species, so it is best to place them in the sand, or somewhere they will not topple over.
These large clams are often interesting because of both size and colour.
Tridacna clams typically are easy to keep, if one has powerful lighting and good water quality. The calcium level of the water should be between 400 and 440 ppm, as this allows the clam to build up its shell. One should however avoid fish and invertebrates that might damage the clam.
Small clams (<4 inch or <10 cm) need a diet of phtytoplankton until they have grown. Larger specimens derive most of their nutrion from photosynthesis, but it is still beneficial to supplement with phytoplankton.
Tridacna clams will become attached, to varying extents, to the rocks or sand over time. Be careful not to damage the foot of the clam when moving them. Placing them in a ceramic bowl made for this purpose might be handy if you need to move the clam.
Pyramid snails often target clams, so make sure to check for these at the foot of the clam. Some types of Wrasses are effective at eliminating these snails.
When choosing a clam, it's good to check that it reacts suddenly to shadows by retracting. If it stays open or has trouble retracting there the specimen isn't healthy.
James W. Fatherree. 2015. On the Giant Clams Tridacna mbalavuana and T. squamosina - Advanced Aquarist - (English)
Bob Fenner. Bivalves: Clams, Oysters, Mussels... Class Bivalvia - Wet Web Media - (English)
Ronald L. Shimek. 2004. Marine Invertebrates (PocketExpert Guide) - TFH Publications / Microcosm Ltd. - (English)
James W. Fatherree. 2007. A Close-up Look at Tridacna crocea - Reefkeeping Magazine - (English)
James W. Fatherree. 2012. Aquarium Invertebrates: A Look at the Giant Clam Tridacna maxima - Advanced Aquarist - (English)
"Minimum volume" indicates the size of the tank needed to house this species under optimal conditions.
This is based on a medium size animal, which you want to keep for several years.
It might be possible to keep smaller specimens for a limited period in a smaller tank. A larger tank might be needed for fully-grown specimens.
"Hardiness" indicates how resistant this species is to disease and how well i tolerates bad conditions in general.
Some species doesn't handle transportation very well, but that doesn't mean that the species isn't hardy under the right conditions.
In this case, a "normal" aquarium is a reef aquarium with mixed corals or a fish only aquarium with an approximately salinity of 1.026 (sg) and a temperature close to 26°C.
Species requiring more than a 4000-liter tank are considered not suitable for home aquarium.
Special aquariums may cover tanks with low salinity, sub-tropical temperature, deep sand bed, sea grass etc.
Always reef safe: No sources indicate that this species will harm corals or other invertebrates.
Often reef safe: Only a few aquarists has reported problems keeping this species with corals and other invertebrates.
Reef safe with caution: This species may be a threat to some types of invertebrates.
Reef safe with luck: Most specimens will harm corals and/or other invertebrates, but you might be lucky.
Not reef safe: This species is a threat to most corals and/or other invertebrates.