Experiments with an Aquarium Ecosystem

Most home aquariums fall into one of three categories: tropical freshwater, warm water marine or reef tank. Once the aquarist has mastered these, he may wish to create his own. Brackish water aquariums, cold water marine aquariums, nano-tanks and biotopes are best tried by experienced aquarists. Do your research before attempting to keep any fish in captivity.

  1. Brackish Water

    • In places where rivers meet oceans you will find a lower salinity than deep ocean water. Whereas sea water usually has a specific gravity close to 1.024, the brackish environment needs a specific gravity of about 1.005. A brackish aquarium can be designed to resemble an estuary, a mangrove swamp or a salt pond. A mangrove swamp or salt pond setup requires slow-moving water flow, while estuary fish prefer high flow. Some interesting fish for estuary setups include bumble bee or knight gobies, figure eight or cylon puffers, celebes rainbows and orange chromides. Most river-dwellers are plant-eaters, so stick to driftwood and rocks in estuary aquariums. Mangrove and salt pond inhabitants include mudskippers, fiddler crabs and archer fish. Mangrove plants, partially submerged, are ideal for these tanks.

    Cold Water Marine

    • A large aquarium with plenty of filtration and flow and a good working chiller can easily become a cold water marine tank. The exact temperature will depend on the fish you plan to keep or the ecosystem you plan to replicate. One of the draws of this type of system is that fish grow larger in cooler waters, so some fairly impressive species can be kept in a cold water system. However, coldwater ocean fish can be difficult to come by in the aquarium trade. Look for fish and invertebrates that inhabit rocky coasts, such as the tompot blenny, beadlet anemone and red-mouthed goby.

    Nano Tank

    • Mini-aquariums, or "nano" tanks, are designed to display smaller specimens that might otherwise go unnoticed in a larger aquarium. Typically, these tanks are under 20 gallons and can be salt or freshwater, depending on the species you wish to highlight. A freshwater nano might display a single male betta splendons or a small school of white cloud minnows. A marine nano might house a tank-bred clownfish, or a couple of basslets or gobies.

    Biotope

    • Whereas many aquariums are a hodge-podge of fish, plants and invertebrates from different waters of roughly the same water quality, a biotope concentrates specifically on one particular ecosystem. Fill your tank with freshwater fish from the Amazon river or replicate the coral reef off the Florida Keys. Focus on making your aquarium conditions optimal for that area, with decorations that mimic the natural environment.