Tridacna Clam - Crocea ClamThere are several different species of Tridacna clams available. There is the T. maxima which gets to be about 12 inches. The T. derasa which gets even bigger than the maxima. Then comes the Tridacna crocea which stays smaller, usually only growing to about 6 inches (15 cm). All of these clam species are quite colorful and eye catching. There are blue, blue-green, brown and other color varieties. T. croceas usually run anywhere from $30 to $100 dollars depending on your location. These clams are very easy to care for, provided that you have high intensity lighting over your tank.For standard sized and shallow tanks you may be able to keep these with power compacts with multiple bulbs. For deeper tanks (those greater than 24 inches deep) you'll need HO, VHO or even better, Metal Halides. They get most of their needed nutrients from photosynthesis and the aquarium light you put over your clam tank is crucial for their well being.
They are also filter feeders and will feed on dissolved nutrients in the water column. They take up ammonia and nitrates and should do ok in aquariums with normal nitrate levels (less than 20ppm).
Placing your clam is important and you don't want to be moving it around all the time. This can stress them and even lead to their demise. Find a spot and stay with it. If you have moderate lighting levels you will want to place them in a crevice in the live rock in the mid to upper regions of the tank. Tanks with higher lighting levels may be able to place them in the sand.
Thats from fishlore.com
Why Keep Tridacnid Clams?
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. Beside that, few if any reef aquarium species have the wide range of vibrant colors that the giant clam species offer as well as the "oooh" factor from non-reef aquarium hobbyists.
Thats from easyreefer.com
Clams benefit an aquarium
Besides their beauty, clams offer one important benefit to a saltwater aquarium: Their ability to filter nutrients from the water. Nutrients in a closed system, like an aquarium, often build to the point where they become problematic. Excess nutrients, like nitrate, lead to problems with low pH, algae and cyanobacteria blooms, and ultimately, poor health with the livestock in the system.
T. maxima clamThe colorful, fleshy part of Tridacna clams that is displayed when the shell is open is called the 'syphonal mantle.' This mantle contains both an incurrent (intake) and an expelling orifice (opening). The clams use these openings to move water through their internal organs, where nutrients and plankton are filtered out and consumed by the clam.
Tridacna clams not only use nutrients from the water to satisfy their nutritional needs, but also employ algae cells called zooxanthellae within their mantle. These algae cells use nutrients from both the clam and the water, and along with light, they photosynthesize. The energy that these cells produce through photosynthesis is then returned back to the clam which uses this energy source to aid in its growth.
The nutrients that clams remove from the water are mainly ammonia and nitrate. When a clam feeds upon ammonia, it eliminates this nutrient from the system before it is processed by the biological filtration. The biological filtration is what facilitates the nitrogen cycle, and by not allowing ammonia to enter into this cycle, the end product nitrate will not be formed. This ultimately reduces the biological load and lowers the overall nitrate level in the aquarium.
Source: Peteducation.com
Ive read it on about 30 sites as i started researching clams. Google "maxima clams ammonia" and you will get a wide range of things. I decided to add one in my fight against hair algae, it wasn't the only thing I added (macro, lawnmower blenny, etc.)
