Fish Aquariums
Fish Aquariums - Fishes and fishing for aquarium and vice versa
Fish are highly sensitive to forest disturbance and therefore the trade also serves as an indicator and direct incentive for forest conservation.
A fish is a poikilothermic (cold-blooded) water-dwelling vertebrate with gills. There are over 27,000 species of fish, making them the most diverse group of vertebrates. Taxonomically, fish are a paraphyletic group whose exact relationships are much debated; a common division is into the jawless fish (class Agnatha, 75 species including lampreys and hagfish), the cartilaginous fish (class Chondrichthyes, 800 species including sharks and rays); with the remainder classed as bony fish (class Osteichthyes).
Several theories on species selection circulate within the community of hobby aquarists. Perhaps the most popular of these is the division of aquaria into either a community or aggressive tank type. Community tanks house several species that are not aggressive toward each other. This is the most common type of hobby aquarium kept today. Aggressive tanks, in contrast, house a limited number of species that can be aggressive toward other fish, or are able to withstand aggression well. In both of these tank types, the aquarium cohabitants may or may not originate from the same geographic region, but generally tolerate similar water conditions. In addition to the fish, invertebrates, plants, and decorations or "aquarium furniture" (all of which may or may not be natural neighbors of any of the fish) are typically added to these tank types.
Species or specimen tanks usually only house one fish species, along with plants, perhaps found in the fishes' natural environment and decorations simulating a true ecosystem. These tanks are often used for killifish, livebearers, cichlids etc. They can be simple as bare bottom with a few necessities or a complex planted aquarium. Some tanks of this sort are used simply to house adults for breeding. Such tanks are common in fish rooms, where people keep many tanks at home.
Ecotype or ecotope aquaria attempt to simulate a specific ecosystem found in the natural world, bringing together fish, invertebrate species, and plants found in that ecosystem in a tank with water conditions and decorations designed to simulate their natural environment. These ecotype aquaria might be considered the most sophisticated hobby aquaria; indeed, reputable public aquaria all use this approach in their exhibits whenever possible. This approach best simulates the experience of observing an aquarium's inhabitants in the wild, and also usually serves as the healthiest possible artificial environment for the tank's occupants.