The true origin of Pacific oyster was from Japan. Their speciality is fast growing and be able to withstand a broad range of environmental conditions. Because of this potential, this species was introduced to many places around the globe to cultivate and create an oyster market where there was not one such as Washington State in 1922 and to France in 1966. The introduction went smoothly around the world except Antarctica where now most widely farmed and commercially. Even though pacific oyster can adapt to any type of habitat conditions, it still have specific needs. The water temperature for this species survive is between -1.8 to 35 degrees Celsius and the salinities that they can withstand between 10% and 38%. This species can be grown anywhere from 40 meters deep through the lower intertidal or subtidal zones and need enough food in the water such as algae, plankton and detritus (filter feeders). However, these species also can be found on mud or sand areas and on the shells of other animals. Magallana gigas are protandrous hermaphrodites (organism that are born male at some point and change sex to female later), most commonly reproduce as male when they first mature and then later develop into female. The sex change depends on food supply. When a high food supply, it reproduce as female and if the food supply limiting, females can revert back to male. The life cycle of Pacific oyster start when these mature adult males and females release gametes into the water column in a giant bloom of 50 to 2000 million sex cells. Few of these sperm and eggs will fertilize and become larvae that float along in the currents. The larvae then develop a small foot, which they can used to move around freely for about 2-3 weeks growing up to 300µm while they look for suitable substrate to attach to for life such as shells, rocks, muddy or sandy areas. After oyster finding the perfect place, it will continue to grow and begin filter feeding their nutrient from the water. It took around one to four year for them to reach sexual maturity depend on the conditions of its habitat. – Elongated rough shell (20-30 cm).- Solid valves but unequal in size and shape. The left valve is slightly convex while right valve is quite deep and cup shaped.- The shells are sculpted with large irregular, rounded, radial fold are often rough and sharp.- The shell colour is usually pale white or off-white.- The shape of shells is varies with the environment.- Have radial ribs on both shells starting from the umbo.- Have adductor muscle (muscle that holds the two shells together) is purple and kidney-shaped.- Have edges of the mantle (the tissue which secretes and lines the shell) is black.- Have a creamy white meat with a firm texture, robust and briny flavour- Hermaphroditic (have both male and female reproductive organs in a single individual)- Reproductive is sexually via broadcast spawning.- Filter feeder that eats plankton and detritus.The Pacific oyster is native to Japan and other areas of northeast Asia but it origin is Japan. This oyster was introduced and cultivated to a many number of countries, almost worldwide using a variety of methods. The main purpose for introduced these oyster was for aquaculture. In North America, the species can be found from southeast Alaska to Baja California, in USA, the species is cultured from Norway to Portugal and also in the Mediterranean Sea. Even in Malaysia also was introduced of pacific oyster that located in East Malaysia. The pacific oyster can adapt any conditions of environment causes it was introduced in worldwide. Even though it can be suitable in any environment, it still has specific needs like water salinity, temperature and food supply.