Giant clams are one of the many wonders of coral reefs. They can grow up to five feet wide, weigh over 400 pounds, and live for 100 years! They power all that bulk by filter feeding microbes and particles from the water, siphoning hundreds of gallons of water per day. Like corals, they also have a symbiotic relationship with photosynthetic algae called zooxanthellae that live in the fleshy part of the clam and provide it with food. Sadly, because they are so beautiful, people like to collect giant clam shells for aquaria and eat the meat inside. The largest giant clam in the Indo-Pacific (Tridacna gigas) was believed to be extinct in Fiji due to overharvesting—but they are being reintroduced. Read more at the Global Reef Expedition blog from the Khaled bin Sultan Living Oceans Foundation.