Some of the introduced predators that are present in Hawaii's wetlands are the mongoose, tilapia, and egret. The mongoose is a threat because it eats the bird's eggs. The cattle egret is selfish because it eats our wetland's food resource even the young and native birds. The tilapia is very aggressive. It feeds on the food resources in the water which keeps the other birds from feasting on the fish.

There are many harmful plants that were introduced to Hawaii's wetlands. They include plants such as the mangroves, koa haole, California grass, salvinia molesta, and other alien invaders. These plants take over and choke the wetland. They can cut off oxygen for waterlife and reduce the growth of other plants such as moss. Some of these plants were brought in to control other plants growth, but soon grew out of control themselves.