Derasa Clam (Tridacna derasa)
The derasa clam is desired by hobbyists for its beauty and fascinating behavior. This animal relies on two very different sources of nourishment. Like many other bivalve mollusks, it filter-feeds on phytoplankton through its gills. However, most of its daily sustenance comes from a symbiotic algae. At a maximum length of about 60 cm, T. derasa is one of the largest of the giant clams. However, it arguably stands out most for its elegant appearance. This species builds a relatively smooth shell and is richly colored with bright gold pigments. See below for more information.Size and Care Requirements
- Purchase Size: Approximately 2″+ 0.5" (length)
- Purchase Size: Approximately 5″+ 1" (length)
- Max Size: 20 cm (7.9″)
- Water Parameters: 72-78° F, dKH 8-12, pH 8.2-8.4, sg 1.023-1.025
- Color: Golden brown (mantle) with darker markings
- Reef-Safe: Yes
- Diet: Omnivore. In addition to consuming products released from its symbiont, this clam is a phytoplanktivore. Thus, it benefits greatly from the regular addition of live phytoplankton.
Derasa Clam Species Information
The derasa clam (Tridacna derasa) occurs from Australia and Fiji to Indonesia, Palau, Solomon Islands, Tonga, Papua New Guinea, the Philippines and Vietnam. Populations have also been reintroduced (after local extinctions) to the Federated States of Micronesia, Guam and the Northern Mariana Islands. Whether living on reef rock, over sand or nestled between corals, T. derasa prefers brightly sunlit habitats. It's dependence on intense light arises from it's dependence on an endosymbiotic dinoflagellate. This photosynthetic algae needs strong, full-spectrum light to survive. The derasa clam is totally reef-safe. Beautiful and interesting, Tridacna derasa adds an exotic touch to any mature, well-maintained reef tank. It can't be kept safely with certain predatory fishes such as triggerfish, puffers, certain wrasses, etc. A sustainable alternative to wild-caught derasa clams, these aquacultured specimens have a comparatively higher survivability.Benefits of Aquacultured Aquarium Livestock
Captive-bred derasa clams provide a huge advantage over wild-caught specimens. Because they are cultured under captive conditions, they are better adapted to living in an aquarium and tend to be more resistant to disease. They are also better capable of handling shipping stress. By purchasing captive-bred organisms, you are supporting the aquaculture of marine organisms and helping make our hobby sustainable! AlgaeBarn keeps these derasa clams in an invertebrate-specific system to minimize the transfer of fish parasites and other unwanted hitchhikers.100% Alive on Arrival (AoA) Guarantee
We guarantee that every derasa clam we sell will be Alive On Arrival and in good health. Should any arrive in any other state, we will either replace them free of charge (including shipping). If the total livestock loss is less than $40, we will issue store credit. For more information, please also visit our 100% Alive On Arrival Guarantee page.

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Our Guarantee
We take the worry out of buying Live Copepods, Phytoplankton, Inverts, and Captive Bred Fish online by going above and beyond to take care of our customers. That’s why we guarantee every order we ship will be 100% Alive On Arrival or we will replace it free of charge. Booya. We’ll even cover the shipping on the replacement no matter which service you choose. Double Booya.
About our policy: When your order arrives, be sure and inspect the contents to ensure everything is looking alive and well before you add them to your tank or put them in the fridge. We’ll give you 12 hours after delivery to make sure you are completely satisfied.
“We will take care of you and make it right”
If for any reason you decide something isn’t quite ultra grade, simply snap a photo of the unopened item(s) you would like replaced. Be sure to get the expiration date on the back label in the photo. After that, visit www.algaebarn.com/claims and submit the form. We’ll review the photo and have a replacement out to you faster than a six-line wrasse at feeding time.
Captive Bred Fish: We guarantee every Live Fish we ship to be 100% Alive On Arrival and we also offer a 7-day health guarantee on all Live Captive Bred Fish. In the event that your fish arrives DOA (Dead On Arrival), simply take a photo of the fish in the unopened bag/jar within 2 hours after delivery and visit www.algaebarn.com/claims to submit the form. If the fish is DOA, we will offer you a choice of either a full refund or a free replacement, including the shipping cost. If the fish expires from natural causes (this does not include being killed by tank mates, jumping out of the aquarium, being acclimated to the wrong environment, not being fed the recommended foods) within 7 days after delivery, just provide a picture of the expired fish and we will offer you a free replacement, however, you must pay for shipping, or a refund, less the shipping cost. We can offer this industry leading guarantee on all of our live fish because Captive Bred fish are generally healthier and hardier than their wild-caught counterparts!
Invertebrates: We guarantee every invertebrate (Invert) we ship to be 100% Alive On Arrival. In the event that your inverts arrive DOA, simply take photos of the DOA items within 2 hours of delivery and visit www.algaebarn.com/claims to submit the form. We will review the photos and issue store credit for any DOA Inverts!
Once your replacement order is processed, we’ll send you a brand new tracking number automatically. Thats it, pretty simple right?
So start giving your tank the love it deserves and order with confidence knowing that AlgaeBarn has your back.

tgill25 –
I can’t even order it on your website. This is ridiculous!