Brackish-water aquarium - AbsoluteAstronomy.com

A brackish water aquarium is an aquarium

Aquarium

An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

where the water is brackish (semi-salty). The range of "saltiness" varies greatly, from near freshwater to near marine and is often referred to as specific gravity (SG) or salinity. Brackish water aquaria is a popular specialization within the fishkeeping

Fishkeeping

Fishkeeping is a popular hobby concerned with keeping fish in a home aquarium or garden pond. There is also a fishkeeping industry, as a branch of agriculture.-Types of fishkeeping systems:...

hobby. Many species of fish traded as freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

species are actually true brackish species, for example mollies

Poecilia sphenops

Poecilia sphenops is a species of fish, of the genus Poecilia, known under the common name molly; to distinguish it from its congeners, it is sometimes called short-finned molly or common molly. They inhabit fresh water streams and coastal brackish and marine waters of Mexico...

, Florida flagfish

Flagfish

The flagfish or American flagfish, Jordanella floridae, is a killifish native to Florida. It received its name because the male fish resembles the American flag, with a large black/blue dot and alternating red and black/blue stripes on its body. It is a common, native fish in Florida that is...

, and some cichlid

Cichlid

Cichlids are fishes from the family Cichlidae in the order Perciformes. Cichlids are members of a group known as the Labroidei along with the wrasses , damselfish , and surfperches . This family is both large and diverse. At least 1,300 species have been scientifically described, making it one of...

s such as chromides

Etroplus

Etroplus is a small genus of cichlids with only three species. They are found in southern India and Sri Lanka, where they are the only native cichlids.Their closest living relatives are Paretroplus from Madagascar...

and black-chin tilapia

Tilapia

Tilapia , is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapia inhabit a variety of fresh water habitats, including shallow streams, ponds, rivers and lakes. Historically, they have been of major importance in artisan fishing in Africa and the...

. There are also several popular species traded purely as brackish water fish, including monos

Monodactylidae

The Monodactylidae is a family of fish within the Perciformes commonly referred to as monos, moonyfishes or fingerfishes. All are strongly laterally compressed with an approximately disc-shaped body and tall anal and dorsal fins. Unusually for fish, there are scales on the dorsal fin and sometimes...

spp, scats

Scatophagidae

The scats are a small family, Scatophagidae, of fishes in the order Perciformes.They are small fish native to the Indian and western Pacific Ocean that have been popular in the aquarium trade in the last 30 years...

, archerfish

Archerfish

The archerfish are a family of fish known for their habit of preying on land based insects and other small animals by literally shooting them down with water droplets from their specialized mouths...

, and various species of pufferfish

Pufferfish

Tetraodontidae is a family of primarily marine and estuarine fish of the Tetraodontiformes order. The family includes many familiar species which are variously called pufferfish, balloonfish, blowfish, bubblefish, globefish, swellfish, toadfish, toadies, honey toads, sugar toads, and sea squab...

, goby

Goby

The gobies form the family Gobiidae, which is one of the largest families of fish, with more than 2,000 species in more than 200 genera. Most are relatively small, typically less than 10 cm in length...

, flatfish, and gar

Gar

In American English the name gar is strictly applied to members of the Lepisosteidae, a family including seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine, waters of eastern North America, Central America, and the Caribbean islands.-Etymology:In...

. Generally, aquarists need to maintain a specific gravity

Specific gravity

Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...

of around 1.005 to 1.010 depending on the species being kept, but practically all brackish water fish tolerate variations in salinity

Salinity

Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...

well, and some aquarists maintain that regularly fluctuating the salinity in the aquarium actually keeps the fish healthy and free of parasites.

Aquarium Maintenance

Brackish water species can be kept mainly the same as standard freshwater aquaria, but use a hydrometer to check the salinity of the water. Certain kinds of brackish water fish need to have their salinity increased slightly every 6 months. The tank sizes can vary widely depending on the needs of the particular species, and the temperature is usually in the tropical range of 76-82 degrees Fahrenheit. The substrate can vary from sand to gravel, but many aquarists choose crushed coral or aragonite sand, both of which help raise the hardness and pH to an acceptable level. Many brackish water fish, as any fish, can jump out of the tank, so it must be covered. However, many of them can breathe out of the water for over an hour. Some brackish water species come from estuaries. These should have a slow moving current and some hiding places in their aquarium. Some come from larger rivers. These should have plants around the perimeter of the aquarium with some large rocks to rest on. Others come from mangrove swamps. These should have a few mangrove plants, and some species should have a beach to climb out on. Some freshwater species are hardy enough or survive better in brackish water, such as the black-fin shark, polypterus bichirs, certain loaches, danio rerio, all kinds of mollies but especially the Yucatán, and some gobies. All can tolerate the same amount of salt in aquaria, but acclimate them slowly.

Aquarium Maintenance

See also

External links

Further reading