Blackwater Biotope Aquarium Setup

A biotope aquarium is one that aims to imitate a natural habitat. Reef biotopes, for example, show a diverse array of marine fish native to a single reef ecosystem. As an aquarist, one of my favorite biotope set-ups is the classic black water evironment. These earthy, enchanting fish tank set-ups maintain a rustic, natural beauty and lack the gaudy aura of more "artificial" habitats.

In the wild, black water ecosystems occur in several parts of the world, including Southeast Asia, the Southern United States and several branches of the Amazon river. Black water ecosystems are named for their tea-stained appearance; tannins from peat and driftwood give the water a transparent but brown-tinted hue.

Some of the most beautiful tropical fish on the market originate in these ecosystems. The ever-popular neon tetra, for example, developed its bright colors so that individuals could identify one another within the tannin-rich waters of the Amazon. Many other dazzlingly colorful fish, including dozens of species of tetra, danio, loach and cichlid, thrive in wild black-water ecosystems and home black water set-ups.

To set up a black water tank, determine which ecosystem you intend to mimic. It's best to use a large aquarium of 55 gallons or more, but a five-fish school of small tetras may thrive in a black water tank of five gallons or smaller. Spread a thin layer of dark-colored sand or gravel on the bottom of the tank. Organize the space with roots and driftwood, laying them in a manner that creates plenty of hiding-spaces while also supplying open water for swimming. The driftwood or roots will gradually leach tannins into the water, giving the black water aquarium its characteristic tea-stained appearance.

Keep the filter on its slowest setting; black water fish generally prefer calm waters. Peat filtration is ideal, but not essential, for a black water biotope aquarium. You can jump-start your tank using a commercial black water extract; these products are sold at some specialty stores and contain extracts of peat and driftwood.

Some blackwater ecosystems contain plants, while others do not. An Amazon root ecosystem rarely contains many benthic plants; the intense shade and dark, acidic waters make it an imperfect environment for plants. Nevertheless, plants will not harm black water fish and may help to keep the tank's nitrate and ammonia levels suitably low. Set up your black water biotope aquarium with only minimal lighting; a single fluorescent tube should suffice.

Cycle your black-water tank without fish; give the water time to stabilize before adding your first shoal. Check water parameters regularly. Your tank is ready to stock when the nitrate levels are consistently below 10 ppm and ammonia levels are consistently undetectable. The water should remain soft and slightly acidic; an ideal black water biotope has a pH of 5.5-6.5 and has a hardness below 8 dH. Unless you are keeping only cold-tolerant tetra species, a heater is a must-have for your black water biotope aquarium set-up.

To maintain a natural biotope theme, select fish with similar origins. A South American black water tank could contain a shoal of twenty surface-dwelling tetras, such as hatchetfish, jewel tetras or rummy nose tetras. A small group of South American cichlids, such as angelfish or discus fish, act as the centerpieces for this aquarium; a school of corydoras catfish complete the mix. In small tanks, a miniature set-up might include a single angelfish, a school of five cardinal tetras, and three corydoras.

The Southeast Asian equivalent of this set-up would include a large shoal of cyprinids. Twenty to thirty tiger barbs or harlequin rasboras look dazzling schooling together in a large black water biotope tank. Instead of using cichlids as the centerpiece of this tank, the Southeast Asian version would include a small group of four to six large gourami-- choose between the several domesticated strains of the pearl gourami. A shoal of eight to ten clown loaches or dwarf loaches would make this system ecologically complete.

When setting up and maintaining your black water biotope fish tank, be sure to check your water parameters frequently, Many of the fish found in wild blackwater ecosystems are rather demanding; monitor your fish's health frequently. Perform routine maintenance water-changes, but use caution to prevent abrupt shifts in pH caused be reduced tannin levels. Black water biotope aquariums are hard work, but they pay you back for it by granting you a slice of nature in your own home.