Brackish water is water that is saltier than fresh water, but not as salty as sea water. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur naturally, as in brackish fossil aquifers. Technically, brackish water contains between 0.5 and 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (ppt or ‰). Thus, brackish covers a range of salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space and/or time.
The term brackish water derives from the Low Saxon word brackwater, which is the water of a brack. A brack is a small lake created when a storm tide breaks a dike and floods land behind the dike.
Brackish water aquaria
Keeping brackish water aquaria is a popular specialization within the fishkeeping hobby. Many species of fish traded as freshwater species actually do better in brackish water, for example black mollies, Florida flagfish, and some cichlids such as orange chromides. There are also several popular species traded purely as brackish water fish, including Monodactylus spp, scats, archerfish, and various species of pufferfish, goby, and flatfish. Generally aquarists need to maintain a specific gravity of around 1.005 to 1.010 depending on the species being kept, but practically all brackish water fish tolerate variations in salinity well, and some aquarists maintain that regularly fluctuating the salinity in the aquarium actually keeps the fish healthy and free of parasites.
- Brackish Water Aquarium FAQ (http://homepage.mac.com/nmonks/aquaria/brackfaqpart1int.html)
Brackish bodies of water
- Baltic sea
- Lake Pontchartrain, north of New Orleans, Louisiana
- Hampton Roads, Virginia
- Pulicat Lake, north of India
- Kaliveli Lake, near India
- Chilka Lake, in Orissa state, India
- The Rann of Kutch, on the border of Pakistan
- Lingding Yang, Guangdong, China
- River Thames at London