1. Ecologists warned that releasing piranhas into Hong Kong rivers could unbalance the local ecological system.
2. Piranhas and fresh water white butter fish are from the Amazon River and belong to the same species.
3. It is no wonder piranhas are found in rivers around the country.
4. The Fishery Bureau of the Ministry of Agriculture issued an urgent circular in 2002 that required local governments to control piranhas.