A brackish aquarium is an exciting challenge for the aquarium hobbyist. Read more to learn the types of fish and plants that are recommended for brackish tanks.
When it comes to classifying types of aquariums, the delineation between freshwater and saltwater is not enough. Recently, aquarium hobbyists have begun to explore new, specialized types of aquariums like the cold water marine tank and brackish aquariums. Brackish water is naturally found in coastal streams, rivers, and saltwater swamps where saltwater mixes with freshwater. Thus, a brackish aquarium is an aquarium whose water has a higher salinity than freshwater. While many fish are tolerant of various water conditions, certain breeds are more apt to thrive as brackish aquarium fish. Fish that are found naturally in brackish waters, and those inclined to adapt to higher saline environments, do best in a brackish aquarium.
Brackish Aquarium Fish
Guppies = The fantail guppy is a very easy fish to keep and it is well-known for being tolerant of varying water conditions which makes it a perfect fish for the brackish aquarium. Guppies are peaceful community fish that do best in groups of three or more and they tend to breed prolifically. Mature female guppies reproduce as often as every 28 days, bearing between two and 50 fry each time. Guppies vary in color and size - females tend to be larger and less brightly colored while males usually only grow to an inch and a half in length and exhibit a wide range of colors and patterns.
Mollies = Like guppies, mollies are known for being very easy to keep and they do very well in community tanks with others of their species. Mollies are livebearers that are naturally found in coastal streams as well as in brackish and marine waters. This breed of fish is very hardy and can tolerate salinity levels up to 87 ppt. There are many different breeds of molly including the black molly, the sailfin molly, dwarf mollies and more. In the wild, mollies feed on small insects and vegetation but the home aquarium they enjoy a varied diet of flake, dried, and frozen foods.
Swordtails = Another breed of livebearer, swordtails vary in color from red, to orange, to green. Male swordtails are characterized by a pointed, sword-like extension of their caudal fin. In the home aquarium, swordtails breed easily and frequently and it is wise to keep several females for every male so the male swordtails do not become too aggressive. The swordtail is a very active breed of fish and it is best kept in aquariums ten gallons or larger with others of its species. Though the swordtail can thrive in freshwater, it is naturally found in brackish water around Mexico and Central America so, in captivity, they thrive in a brackish water environment.
Archer Fish = A species of rainbowfish, the Archer fish is known for its black-striped body and the turquoise, yellow, or orange spawning stripe on its fins. These fish are peaceful community fish that can be difficult to keep in the home aquarium because they can grow up to 12 inches and because they are fairly picky eaters. In the wild, Archer fish feed on insects on or above the water's surface and it may be difficult to assimilate them to an aquarium environment for feeding. Archer fish are best kept in a tank with a temperature between 77 and 88 degrees Fahrenheit, a pH between seven and eight, and a one to two percent salinity.
Catfish = There are many breeds of catfish and most adapt well to or are naturally found in a brackish water environment. The Banjo catfish has a black and white body that appears almost flat. It can do well in a brackish aquarium though it may take time to adjust. Shark catfish are a relatively easy breed of catfish to keep but they require a great deal of space. Most catfish keep to the mid and lower levels of the aquarium and prefer live foods over pellets and tablets.
Glassfish = Naturally found in the brackish waters around India and Thailand, the glassfish is fairly easy to keep in the brackish aquarium. This breed of fish is somewhat oval in shape with an arched back and a semitransparent body that appears to change water hardness between eight and 20. Glassfish prefer live foods like tubifex worms and bloodworms but they will also eat flake and frozen foods. This breed of fish is great for a community tank because they are generally fairly peaceful, though males can become territorial during breeding season.
Gobies = There are over 2000 species of goby and some of them are the smallest vertebrates in the world, growing only up to one centimeter in length. Gobies can be found in many different habitats including coral reefs, freshwater rivers, and mangrove swamps. The Bumblebee goby can be kept in slightly brackish water provided the temperature is warm and the water alkaline. The Common goby is more well-adapted to a brackish environment and easily kept in a small aquarium. The Lancer or Knight goby is also good for a brackish aquarium, though it is a difficult fish to keep because it is a picky eater - it prefers live food and may require a diet of live shrimp when it is first introduced into the aquarium.
Fingerfish = Fingerfish, or Mono Angels, resemble angelfish in that they have pointed fins but their fins do not get as long as those of angelfish. Though fingerfish can be kept in either saltwater or freshwater, they do best in an alkaline brackish aquarium. These fish can grow between six and eight inches and they can be difficult to keep because they tend to be very nervous and require a slow acclimation period. Once they get used to the tank, fingerfish are typically peaceful, shy fish that feed voraciously on meat- and vegetable-rich meals of live and frozen foods.
Cultivating a brackish aquarium can be an exciting challenge for aquarium hobbyists and it can also be a great stepping stone to prepare for a marine tank. Brackish aquarium fish come in a variety of beautful shapes and colors from the familiar breeds like guppies and swordtails, to those less common like the Archer fish. When selecting fish for your brackish aquarium, keep in mind the requirements of individual breeds of fish and whether or not they can coexist with others.
Aquarium Plants for Brackish Tanks
Anubias = Anubias are a flowering plant with broad green leaves that anchor themselves to driftwood - they should not be planted in substrate. They are naturally found in the rivers, streams, and bogs of western and central Africa and they do best in subdued lighting. This species of plant does not grow very quickly but given time and the proper environment it can grow to approximately 10 cm. Anubias can tolerate a range of pH levels from 5.5 to 9 and it is very tolerant of varying water conditions. This plant can typically be found at local pet stores or online for between $2 and $5 per bundle.
Java Fern = The java fern is one of the only plants recognized to be naturally brackish that is regularly available in pet stores. This plant is another species that anchors itself to driftwood and it too does best in low lighting. Java fern are native to East Asia and they are very tolerant of varying conditions. This type of fern can grow upwards of 10 inches and they can quickly take over the aquarium unless you are mindful of trimming it back occasionally. Java fern can be found online and at local pet stores for between $3 and $6 a bunch.
Vallisneria = The vallisneria plant, also called vallis, eel grass, or tape grass, are relatively easy to grow in the aquarium and are some of the cheapest to purchase. This plant typically has long, thin leaves, though some dwarf species have leaves that are tightly coiled. Most species of vallisneria do well in tropical temperatures between 72 and 84 degrees Fahrenheit with a moderate pH between 6 and 7.5. These plants are found throughout the world and they can grow to be very large - some varieties growing as long as one meter. Vallisneria can be purchased online and in pet stores for between $2 and $4 a bundle.
Mangrove = Typically found in African swamps, mangroves are particularly well adapted to brackish water. The mangrove is a type of semi-aquatic plant - its roots grow in saltwater but the stems and leaves grow above the surface. This plant thrives in varying water conditions but it is recommended that you keep your mangrove tank between 72 and 78 degrees Fahrenheit and the salinity at a specific gravity between 1.020 and 1.025. Mangroves are an especially useful aquarium plant because they can help to filter out nitrates and phosphates - it is even possible to create a mangrove filter for use in a saltwater aquarium. Mangrove plants are not the easiest plants to find but they can often be found on eBay or live aquarium online retailers for between $10 and $30.
Cabomba = Similar in appearance to hornwort, the cabomba grows quickly and densely which makes it a great plant for use in the background of a brackish aquarium. These plants do well in moderate lighting and thrive in a temperature between 72 and 82 degrees Fahrenheit and in a pH between 6.5 and 7.5. The cabomba is native to the Western hemisphere and it belongs to the same family as the water lily. This plant is readily available at many pet stores and can also be purchased online for between $2 and $5 a bunch.
Hygrophila = Native to India and Sri Lanka, the hygrophila plant is one of the more difficult species of brackish aquarium plants to maintain. This plant requires CO2 and high lighting to thrive and it does best in a pH between 6.2 and 7.2. Under the right conditions, this plant can grow to be quite large and their fern-like appearance makes them popular for use in the home aquarium. There are many different species of hygrophila and it is not often sold in pet stores, but it can be found online at live aquarium retailers for between $2 and $4 a bunch.
Hornwort = Hornwort is a type of floating aquarium plant but it can also be rooted in gravel. It is naturally found in both temperate and tropical streams, ponds, and marshes and they are one of the most popular aquarium plants. Hornwort is very easy to grow and tolerant of many water conditions which makes it an excellent plant for both brackish aquariums and the novice aquarist. Hornwort does best in medium lighting and a small bundle, purchased for between $2 and $4, can quickly grow to up to two feet.
While many plants can adapt to some level of salinity in the water, there are several species of brackish aquarium plants that are especially adapted to a saline environment. Like all plants, brackish water plants require adequate lighting and nutrients in the water to thrive and, with the proper aquarium plant care, some species can grow very quickly. Before you fill your brackish water aquarium, do some research to decide which types of plants will be best for you.