Tridacnid Clams

Keeping Maxima, Crocea, Squamosa and Derasa Clams in Reef Aquariums
Aside from being some of the most intriguing of all reef aquarium species, tridacnid clams actually provide a range of benefits well beyond their beauty and novelty.

Clams are filter feeders, meaning that they help marine aquariums maintain high water quality by absorbing nitrates, ammonia and other organics that are harmful to sensitive reef tank inhabitants even in very low concentrations. Other than that, few if any reef aquarium species have the wide range of vibrant colours that the giant clam species offer.
Keeping giant clams healthy and growing in a reef aquarium requires a similar system of care to that of SPS corals. Bright lighting such as that provided by metal halide is ideal to maintain their vibrant colours, in that most clams generate energy by photosynthesis as well as by filter feeding. Although they also do well under T5 lighting. Moderate to high water flow will ensure that clams receive an ample supply of water to continually feed on. High levels of calcium provided by calcium reactors will help clams to develop thick and healthy shells and to grow rapidly.
There are several species of giant clams available to reef aquarium hobbyists today, each offering colour patterns unique to their species. Today, Maxima clams are among the most popular for their electric colouration and interesting patterns. Some Maxima clams are subcategorised by the characteristics of their markings and are sometimes referred to as Ultra Maxima clams (for their extremely electric blue and purple colors) and the very popular Teardrop Maxima clams (named for the teardrop-shaped markings on their mantles). The Crocea clam species are similar in appearance to Maxima’s, and come in a wide range of colours including those with stripes of greens and teals. Squamosa clams are among the easiest to keep of all of the giant clam species available for reef aquariums. Despite having lower light requirements (often placing these clams directly on the sandbed of the reef tank is the preferred placement), Squamosa clams do come in exciting colour varieties including interesting patterns of spots ranging from brown to blue. Derasa clams continue to grow in popularity for both their ease of care and fast growth. A popular colouration of Derasa clams is known as the “Blue Rim Derasa”, in which only the very edge of the clam’s mantle is a shockingly bright blue color.
Clams are relatively slow growing reef aquarium inhabitants, a trait that is actually considered a positive feature by most advanced reef tank hobbyists. Clams do not encroach on other reef tank species in the way that often corals do, and offer peace of mind as well as beauty for their keepers.