Yup that is the janitor fish.
It is a possibility that someone have thrown them in the bodies of water and because they strive in any condition they have propagated well and in the end they are competing with fishes for food.
The government is even willing to buy this so that people would try to fish them out of the water.
In some industry, they are trying to use it as an alternative fuel. They extract the oil of the fish and process it to become biofuel.
In livestock Laguna lake development is now trying to experiment with it to use it as protein source for feeds.
