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It is not the intention of this section to discuss the cultivation of aquatic plants, their structure, or classification. These details are readily available in any basic aquatic plant book. Nevertheless, since the natural environment of all rainbowfishes includes waterplants; live, flourishing plants are an important part of maintaining a wholesome captive environment. It also provides information which can be used if you want to design a rainbowfish aquarium with plants from their specific part of the world.
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Wim Heemskerk, Netherlands |
In an aquarium, living plants serve most of the same functions that they do in the wild. Plants provide shelter, shade, and for some rainbowfishes - food, especially the duckweeds. Plants in an aquarium also contribute to the oxygen content of the water and assists in maintaining water quality. In addition to this, plants provide huge surface area for colonisation by other micro flora and fauna. In tanks where plants are growing well, rainbowfishes behave more normally and display better colouration. Finally, aquatic plants add to the beauty, interest, and naturalness of the aquarium.
Aquatic plants are not difficult to keep healthy and attractive, as long as their basic requirements are met. As is the case with terrestrial plants, these include adequate light and fertilisation, a suitable growing medium, proper water conditions and temperature. The importance of proper lighting cannot be over-estimated, but too much light is almost as bad as too little light. Keep the aquarium well away from a window and light it by artificial light. In this way you can control the light independently of the vagaries of natural weather; and should not be affected by a rampant growth of algae.
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Wim Heemskerk, Netherlands |
Planted aquariums are often referred to as 'natural' aquaria. However, despite what you may read elsewhere, reproducing in captivity the intricacies of natural aquatic ecosystems is not only a very difficult task, but almost impossible to accomplish with overall success. It implies an aquarium in which all the inhabitants are interdependent on each other, as they are in a natural environment, and it takes very little thought to understand that this outcome could not be achieved in an aquarium.
Strictly speaking a natural aquarium would be one where we wouldn't have to feed the fish, change water, learn water chemistry, provide lighting or any of the other things we have to do to maintain an aquarium successfully. No matter how much we may wish it, regrettably, there is no such thing as a natural aquarium. Keeping rainbowfishes in an aquarium cannot, even under the best conditions, be anything equal to their life in the wild. At best, an aquarium is an artificially controlled environment that is suitable for maintaining fishes, plants, and other aquatic life forms for an extended period.
In a loose sense, however, a 'balanced' aquarium is attainable, by not overcrowding the fish, by stocking with plenty of plants, and by way we are imitating Nature, even if we have to help her by feeding the fish, trimming the plants, and removing from time to time much of the sediment that collects on the bottom. A state of balance would occur if everything (food, lighting, fertiliser, etc.) that we supply the aquarium is taken up by the fishes, aquatic plants, algae and other life forms to the same degree as they are being supplied.
Many hobbyists are disturbed by the presence of algae and do their best to try and remove it. Perhaps this should be taken as evidence that a 'state of balance' is occurring. Maybe not the particular state of balance that you desire, but it is a biological balance all the same. However, the truth is that no matter how biologically balanced your aquarium is, over time water quality will deteriorate and must be changed on a regular timetable.
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Wim Heemskerk, Netherlands |
The aquatic flora of Australia is not dissimilar than that found in other tropical or subtropical regions of the world. Although some endemic species are found, most species are cosmopolitan. This relatively low degree of endemism and diversity in aquatic flora is probably because of the universal nature of many aquatic plant species. Long-distance dispersal of aquatic plants by birds has been well studied. The pattern of bird migration to and within Australia closely fits the distribution pattern we see in the aquatic flora. Most of our migrants come from the Northern Hemisphere (as opposed to coming from the east or west). When they reach our tropics they may move freely from east to west or vice versa, helping explain the similarities of these floras. The birds that move south to temperate zones do so directly (most down the east coast) and there is very little movement from east or west. Comparatively few fly to Tasmania, South Australia or south-western Western Australia. However, very few comprehensive aquatic flora surveys have been conducted within Australian freshwaters.
The aquatic flora of New Guinea has not been studied to any significant degree neither. Many of the river mainstreams are turbid, which precludes the establishment of submerged aquatic macrophytes. The number of species is probably less than 200. However, species-level treatments exist for only a small portion of the flora. The vegetation of New Guinea is more closely allied to the flora of western Asia than to that of the Australian continent. For this reason it has been termed "Malesian", part Asian and part Melanesian.
Australian Aquatic Plant Communities
Floating and floating-leaved plants occur in permanent waters in most coastal rivers across Australia. Typical northern assemblages include Nelumbo nucifera, Nymphaea, Nymphoides, Ottelia, Azolla, Ludwigia, Marsilea and Pseudoraphis species. These may be found in the river channels and pools in the tropical coastal plain. On the floodplains of the Northern Territory and the Kimberly, such assemblages may be fringed by Melaleuca swamp forests.
In coastal river systems in sub-tropical eastern Australia, species include Azolla, Nymphaea, Potamogeton, Ottelia, Nymphoides and Lemna species. In the south-west of Australia, Najas, Myriophyllum, Lemna, Azolla, Spirodela, Potamogeton, Nitella, Chara and Ottelia species dominate. Inland aquatic communities associated with the Murray-Darling river system include Azolla, Potamogeton, Spirodela and Lemna species. While the water level maintaining such communities usually remains between one and two metres in depth, it may dry out completely for periods. Some lakes support floating plants such as Ludwigia, Azolla or Lemna species.
Most of the above wetlands are fringed by submerged and emergent herblands in shallower waters. In northern Australia, species include Triglochin, Caldesia, Limnophila, Ludwigia, Ceratophyllum, Monochoria, Vallisneria, Utricularia, Myriophyllum, Eriocaulon and Chara species. Species associated with such communities in coastal eastern Australia include Ludwigia, Najas, Vallisneria, Triglochin, Myriophyllum, Potamogeton, Nitella and Utricularia species.
Wet grasslands are most extensive in northern Australia and are characterised by the presence of Pseudoraphis, Panicum, Paspalum, Leersia, Echinochloa, Cyperus, Eleocharis, Fimbristylis, Fuirena and Scirpus. This assemblage occurs mainly on seasonal floodplains. To the south in Queensland and northern New South Wales, wet grasslands consist of Paspalum, Amphibromus, Juncus, Carex, Echinochloa and Panicum. Sedgeland communities are also common in coastal Australia.
© Copyright Adrian R. Tappin
Updated December, 2008
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