How long do oysters live in saltwater oyster tanks? This is a common question among experienced or amateur aquarists. While it is not clear-cut, there appears to be a general consensus among many aquarists that freshwater oysters do not live very long in saltwater tanks. According to some reports, a freshly purchased oyster in a saltwater tank may only live six days. But, when properly maintained, the lifespan of fresh oysters exceeds ten years.
The lifespan of oysters during their first year in fresh water may depend on the type and size of oyster, water temperature, available water and lighting conditions, among other factors. When they are newly bought, mature oysters may survive for only a few days at most in a standard glass, plastic or metal aquarium. In a tightly sealed freezer, however, mature oysters may not survive for more than a few weeks. Once an oyster has entered its dormant period, the only way to extend its life is by rearing it in a fresh water aquarium. Reared or re-caught oysters may be kept in a freezer for up to one year.
Once they are in a new aquarium, they need a steady supply of light, fresh air and water. Freshwater oysters will settle down into a dark corner of a room temperature aquarium, called a grower tank. They will not thrive unless a light is available for at least six hours every day. If this light source is unavailable for more than a week, re-occurring feeding should be done using a commercially prepared berry shuck, baby mussels or seaweed.
When a newly bought oyster comes out of the shell, it is covered with a hard exoskeleton made of calcium carbonate. Within two days, it should be able to absorb calcium carbonate from the seawater. If this process does not take place, the shell could collapse, trapping the oyster inside. If the oyster is successfully kept inside the shell, it will emerge with a hard exoskeleton that will break down into a hardy stage called a nub, which cannot be eaten.
Young nub oysters may survive for a few days but will be unable to support a body weight. After this period, they start to drift towards the upper parts of their aquarium tank, where they settle down and grow into a new pair of juvenile oyster. For the first month, they grow very slowly, reaching about one inch per day. During this period, the oyster will stay tightly closed, forming a kind of cocoon around itself.
As the oyster grows, it will slowly open its exoskeleton and fill the growing stage of its development. This process can take up to four months, during which time they usually last between one and five months before they fall off. Although most fresh-water oysters will grow to adulthood, those from saltwater tanks will usually last longer.
Fresh water oysters are normally sold by the bag or by the scoop. They are packed in muslin bags or in plastic ice boxes that have been sealed and secured with tape. The meat of the oyster is sold separately. Those from which fresh water oysters are harvested will have their shells cut open and their insides cleaned prior to being packed. Those from saltwater tanks will normally be harvested without their shells, and the meat will be sold on the basis of weight.
When the water temperature rises above about 48 degrees Fahrenheit, the shucked oysters will burst open, allowing the inside to escape air and moisture, but they will keep the head intact. This allows them to breathe and to decompose, eventually releasing their contents. They will then begin to decompose until there is little organic matter left. This process is called suffocating, and it can take as long as two months before all the organic matter has been decomposed enough to make it viable for eating. Once this has been done, however, fresh shucked oysters will always be available at seafood restaurants around the world.