Freshwater biodiversity is highly threatened today - a fact that should be on the mind of every serious aquariast. The natural habitats of tropical freshwater fish are increasingly threatened by human activities, and while at times the hobby has been been at odds with conservation, the role of aquariasts in preserving species is growing in importance.

As their natural habitats are lost, freshwater fish species are disappearing. A Malaysian study found fewer than half of the 266 resident fish species, while more than 30% of Singapore's fish species are thought to be extinct. Freshwater biodiversity is highly vulnerable. Habitats tend to be largely discontinuous meaning species cannot easily cross land barriers that separate lakes and watersheds. Thus freshwater fauna is generally localized, static, and subject changing conditions. Whereas terrestrial species simply migrate in response to habitat changes, freshwater species must cope with ecological and climatic changes in order to persist.

Freshwater habitats are facing an onslaught of threats from deforestation, waterway modification and dam construction, the introduction exotic species, pollution, and over exploitation. Deforestation in particular has major consequences for species popular in the hobby. Erosion and the loss of habitat can severely affect fish populations. Similarly damaging, the introduction of non-native species (exotics) can devastate the local fauna as in the case of the Nile Perch in Lake Victoria which has caused the extinction of endemic Haplochromines.

Collection for the hobby has had a direct impact on some species to the extent that they have become locally extinct over parts of their ranges. For example the Bala shark is highly threatened in its native Sumatra and Borneo due to its popularity as an aquarium fish. In the past the Bala Shark (Balantiocheilus melanopterus) was heavily collected since it did not readily reproduce in captivity (this has changed as Balas are now captivity bred in fish farms). To optimize exploitation, collectors targeted breeding grounds where Balas congregate for mass spawning. The removal of breeding adults coupled with loss of habitat from deforestation significantly impacted local populations. Similar over harvesting has been documented among characins and the Arowana.

Today the role of aquariasts in conservation is changing. As habitat loss continues -- especially the destruction of tropical forests -- the importance of aquariasts in conservation is expanding. Aquariasts are helping to maintain species (such as Cherry barbs and certain Killifish) that are essentially extinct in the wild. By keeping these species and populations viable, the fish-keeping community is protecting against extinction. When and if reintroduction to natural habitats becomes possible, it will be in part thanks to aquariasts.

Time has effectively run out for many species. Aquariasts can do their part in preventing the further extinction of some freshwater fish.