The grass puffer (Takifugu niphobles) is a species of fish in the Tetraodontidae family. It is found in Korea, Hong Kong, Japan, Taiwan, and Vietnam. They are popular for children to catch and possibly in aquarium trade, but cannot be eaten on account of fatal tetrodotoxin (pufferfish poison) which can cause heart problems, kidney failure, and a coma that can be mistaken for death.