The Jelly fish became over populated in the black sea, because of over fishing, and uncontrolled agricultural runoff.
The camel was imported, for transport, and exploration. (especially for the harsh conditions of the outback)
The piranha is very confusing, and people are still trying to figure out how they got to the United states, because they are found in very small numbers across the US, but seem to thrive in California, it is believed that they were smuggled into the US.
