Researchers have cultivated certain fry in normal seawater and seawater containing twice the concentration of carbon dioxide. The fry grows up and are placed in a maze. Whenever they encounter obstacles, fish hatched in normal seawater will choose the right direction to avoid the obstacles. However, the fish that hatched under high carbon dioxide concentration will randomly choose to turn left or right, so that this fish has a reduced chance of survival when encountering natural enemies. 
About one-third of the carbon dioxide produced by humans burning fossil fuels is absorbed by the oceans on the earth, which makes the sea water gradually acidic, which will soften the shells and bones of marine organisms.
 the researchers believe that the ability of fish to survive in a high carbon dioxide environment will be weakened.