New Guinea River
New Guinea is located north of the Australian continent and is the world’s second largest island. At one time it was joined to the Australian main land but separated when the area known as the Torres Strait was flooded over during the last glacial period. This is why the fish species that are found in New Guinea resemble those from Australia more so than the fish species from Southeast Asia.
The western side of the island contains the provinces of Papua and West Papua, the eastern side is the independent country of Papua New Guinea.
The main species of fish to be exported from this island is the Rainbow fish, this species is also divided into several sub species.
The water conditions are very easy to replicate being in the middle regions of hardness (4 - 8 DH) with the pH from 6.5 - 7.1. Water temperatures are on the lower side of tropical 23 - 25°C.
Setting up the tank
A minimum tank size of 200 liters (44 gallons) is recommended for this biotope as rainbow fish do require a lot of swimming space; a lid is also a must as these fish are well known to be jumpers.
Keep the planting to the rear of the tank and use sand as the substrate. Adding river rocks on top of the sand works well, bright lighting is also a must.
Plants for the tank
Vallisneria used as a back ground plant will give a good banking effect, mix in with some Aponogeton for a varied back drop. Ceratopteris (Indian fern) can either be used as a floating plant or mid ground planting, mix this with some Bolbitis (African Water Fern) but keep the front of the tank unplanted to provide the free swimming area
Fish for the tank
As mentioned earlier in the article, this is the perfect biotope for rainbow fish. There are several species but the most common available has to be the Bedotia. Adult size for these fish is 6 inches so a tank of at least 48 inches in length will be required. These are a schooling fish, a group of at least 4 fish will keep them happy.
Freshwater gobies, in particular the pygmy goby, will add some interest to your tank. Always make sure that the species of goby you are purchasing is suitable for a freshwater set up, many species are happiest in brackish or even saltwater conditions.
Arius catfish, commonly known as the shark catfish are always on the move. I have kept several of these in the past and they are a very tolerant species but they can grow up to 15 inches in captivity, be aware of this when adding them to your aquarium. This species of fish also prefers to be kept in groups of at least 4 fish.
All of the above mentioned species will feel more at home with the addition of some salts to the water but add this in a mild dose.
Sources of information
Rhett A. Butler/mongabay.com, wikipedia