Be conscientious when disposing of tropical fish
I hope it goes without saying that life has exploited almost every possible inch of planet earth. It should also be noted that some organisms have evolved to survive and prosper in very particular places. The problem occurs when non-native species are introduced into a habitat that they are more competitive than natives and can overrun. Because of this, you must always be conscientious when disposing of tropical fish, either dead or alive.
If a fish in your care dies, it should be wrapped in a plastic bag and discarded to a normal landfill, not simply flushed down the toilet. The disease or problem that caused the death might be biological in nature, and since it probably was not native to the new environment, could become a problem in the waterways of your area. Accidental introduction of parasites and bacteria can become quite a problem if unchecked by natural predators in a new ecosystem.
Even more devastating, though is when people find disposing of tropical fish they no longer want to keep is easiest by releasing them into native waters. Just one example of the devastation that can be wrought by non-native species introduction is found at a local Japanese pond where the native fish are fighting for their lives.
Starting in 2007, with approval from the Tokyo Metropolitan Government, the group began capturing bluegill and black bass — freshwater species indigenous to North America — in the pond to protect its native species and ecosystem.
Disposing of Tropical Fish can cause an environmental Catastrophe
This pond is being taken over by a couple of totally foreign fish – native to North America which may have been a convenient place for local fish keepers in disposing of tropical fish by releasing them into native waters. Since there are no natural predators released at the same time, the non-native species can often have an unfair advantage and completely unbalance the native eco-sphere, where the native species can become endangered.
This is not always the result of careless or uneducated fish hobbyists. Guppies have been introduced on more than one occasion to malaria ridden areas in an effort to drop the mosquito population and this sudden invasion of non-native fish has disrupted the natural balance of the rest of the system in many ways.
Many times, the fish that are flushed down the drain as a convenient way to get rid of them may survive, and if they do, they are often aggressive fish in an aquarium, piranha have learned to live in much cooler areas than their native habitat, and have caused problems. Disposing of tropical fish should never be release into the wild local water bodies. If you must, give the fish to the local pet store or a friend, NEVER release ornamental fish into the local habitats,there could many unforeseen devastating repercussions on that fragile balance.