[Ebook] Encyclopedia of Aquarium & Pond Fish – Directory of Freshwater Fish – Brackish water species

Directory of Freshwater Fish

Brackish water species

A brackish-water tank lets you keep a number of interesting, but often overlooked, species that are native to estuarine waters. The home aquarium can be a mixed community setup, or a recreation of a specialized habitat such as a swamp. It could incorporate mangrove plants and mudskippers, which venture out of water more regularly than any other fish. Brackish-water tanks are not difficult to maintain; correct water conditions are initially achieved by adding a small amount of sea salt. Some of the more adaptable aquarium plants will grow in these surroundings, although plastic substitutes can also be used.

Mono (Monodactylus argenteus)

• ORIGINS: Range extends from East Africa eastward as  far as parts of Indonesia and Australia.
• SIZE: 10 in (25 cm).
• DIET: Live foods and vegetable matter.
• WATER: Temperature 72–77°F (22–25°C); alkaline (pH 7.6–8.0) with SG 1.002–1.007.
• TEMPERAMENT: Peaceful, but avoid small companions.

Although largely silver, the Mono’s patterning does differ to some extent between individuals. The prominence of the black banding through the eye and behind the gills is variable, as is the amount of yellow coloration on the fins. Monos look most effective if kept in a group. They are elegant but rather nervous fish by nature.

Siamese Tigerfish (Datnioides microlepis)

• ORIGINS: Southeast Asia, in parts of Cambodia (Kampuchea), Thailand, and on Sumatra and Borneo.
• SIZE: 16 in (40 cm).
• DIET: Live foods of various types.
• WATER: Temperature 72–79°F (22–26°C); alkaline (pH 7.6–8.0) with SG 1.002–1.007.
• TEMPERAMENT: Predatory.

The vertical yellow and black stripes of these fish help to explain their name. Their dorsal fin has a decidedly spiky appearance. Although Siamese Tigerfish are unlikely to grow as big in aquariums as they do in the wild, juveniles will still ultimately need a large tank. Siamese Tigers cannot be trusted with smaller companions, since other fish naturally form part of their diet.

Glassfish (Paramsassis ranga)

• ORIGINS: Asia, found throughout India, Myanmar (Burma), and Thailand.
• SIZE: 3 in (8 cm).
• DIET: Live foods of various types.
• WATER: Temperature 77–79°F (25–26°C); alkaline (pH 7.6–8.0) with SG 1.002–1.007.
• TEMPERAMENT: Instinctively rather nervous.

The internal organs of Glassfish are visible through their skin. Males have a more pointed swim bladder and bluer edges on their fins. Spawning can be induced by raising the water temperature. Up to 150 eggs are scattered among plants. They hatch in a day, and the fry are free-swimming soon after. These fish are sometimes injected with bright dyes and sold as “painted glassfish”; even if they survive, their garish colors will fade after a few months.

Lesser Spiny Eel (Macrognathus aculeatus)

• ORIGINS: Southeast Asia, in brackish environments close to the shoreline.
• SIZE: 14 in (35 cm).
• DIET: Live foods of different types.
• WATER: Temperature 73–82°F (23–28°C); alkaline (pH 7.6–8.0) with SG 1.002–1.007.
• TEMPERAMENT: Predatory and aggressive

The distinguishing features of this species are the alternate light and dark horizontal bands along the side of the body and the false eye-spots on the dorsal fin. As with other spiny eels, there are a number of spines in front of the dorsal fin itself. Nocturnal by nature, and eager burrowers into the aquarium substrate, Lesser Spiny Eels do not rank among the most conspicuous of aquarium occupants. They will hunt for food on the floor of the tank, so provide them with foods that sink to the bottom. Spiny eels tend not to agree with one another when kept in small groups.

Mudskipper (Periophthalmus barbarus)

• ORIGINS: East Africa, south to Madagascar, and east to parts of southeast Asia and Australia.
• SIZE: 6 in (15 cm).
• DIET: Live foods of all types.
• WATER: Temperature 77–86°F (25–30°C); alkaline (pH 7.6–8.0) with SG 1.002–1.007.
• TEMPERAMENT: Territorial.

An aquarium for these fish needs to be relatively large and have a raised area like a beach at one end to allow the fish to hop onto land, just as they would at low tide in the wild. Tree roots and plants, too, will be needed, and an external power filter is essential to maintain the water quality. Keeping the aquarium covered will help to ensure that the air inside is warm and humid when the mudskippers emerge from the water.

SANCTUARY IN THE SWAMP

Mangrove swamps occur in tidal areas, often close to estuaries, where salt-tolerant plants grow in the mud. The tangled mass of the plants’ submerged roots provides sanctuary for the young of fish, such as the Tiger Scat (see bottom left), which slip easily between the roots and out of reach of larger predators. Mudskippers in particular have adapted to the mangroves, because they can survive temporarily out of water on the exposed mudflats at low tide, as visible below. When the tide comes in, the mudskippers’ brown, mottled coloration helps to camouflage them as they lie on the muddy bottom.

Tiger Scat (Scatophagus argus)

• ORIGINS Indo-Pacific region, from the coasts of India extending eastward to the Pacific islands.
• SIZE 12 in (30 cm).
• DIET Largely vegetarian.
• WATER Temperature 77–79°F (25–26°C); alkaline (pH 7.6–8.0) with SG 1.002–1.007.
• TEMPERAMENT Social and nonaggressive

The spotted patterning that characterizes young Scats alters as they mature, with the background color becoming silvery rather than golden. Being vegetarian, these fish will damage or destroy living plants in their aquarium. Java Fern (Microsorum pteropus) must not be incorporated, since it may be toxic to Scats if they eat it. Scats are active fish by nature, and a group will require a large, spacious aquarium.

Bumblebee Goby (Brachygobius xanthozonus)

• ORIGINS: Southeast Asia, in brackish waters close to the shoreline.
• SIZE: 2 in (5 cm).
• DIET: Small live foods preferred.
• WATER: Temperature 77–79°F (25–26°C); alkaline (pH 7.6–8.0) with SG 1.002–1.007.
• TEMPERAMENT: Territorial by nature.

The yellowish-orange and black banding on these small gobies resembles that of a bumblebee. Males tend to be more brightly colored and thinner than females. Bumblebee Gobies spend their time close to the bottom of the tank. Their eggs, which are susceptible to fungus even in brackish water, are hidden under a rock and guarded by the male until they hatch about four days later. Provide retreats to lessen displays of territorial aggression.