Amphibious. The dragon can breathe air and water.
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (1d10 + 2) piercing damage plus 3 (1d6) poison damage.
Poison Breath. The dragon exhales poisonous gas in a 15-foot cone. Each creature in that area must make a DC 11 Constitution saving throw, taking 21 (6d6) poison damage on a failed save, or half as much damage on a successful one.