The first one is flooding and endangering other fish. The introduction of scavengers was originally thought to be very beneficial. It was thought that putting them in fish ponds could keep them clean and handle a lot of sundries. However, what I didn't expect was that scavengers not only ate sundries, but also ate weaker fish and fish eggs. Scavengers always liked to harm aquatic plants in water tanks, and they always liked to bully injured ornamental fish, which made the survival of a large number of fish seriously threatened. The flood of scavengers has caused fatal injuries to many native fish.
Second, the scavenger has no edible value and is not easy to destroy. Scavengers always eat garbage or fish excrement, and there are many germs or parasites in their bodies, which makes many people feel that scavenger fish is very unsanitary and has no way to eat. This kind of creature has strong viability, and it is impossible to control the number of scavengers by natural death. Their shells are very hard, and they have natural enemies in its place of origin, so that scavengers will not be flooded, but here it is no threat at all.
At the beginning, scavengers were introduced as ornamental fish, but people did not understand the habits of scavengers and blindly introduced them, which made the scavengers become a big problem for people, especially in the south, which threatened the survival of many fish. If scavengers kept flooding, many fish would definitely become extinct. It is also expected that the flood of street sweepers can be well controlled in the future.