gas
gas
gas
gas
gas
Oil and natural gas.
the gas is may be another chemical that the fish can breath at the surface an can help to make the fish can breath at small air and big water.
Fish do not respire substance in the gas phase, the compound that "is given out" is Carbon Dioxide (in solution).
the gas that released by fish is a carbon that the fish can live at the water without a air. and the fish can not live if without small amount of air. and process by breathing with amount of air that all the animals and humans can breath.
yes, large ammounts are toxic to fish.
liquid???
Solid