Marple (5e Creature)
From D&D Wiki
Tiny fey, neutral
Amphibious. The marple can breathe air and water.
Bubble. Ranged Weapon Attack: +3 to hit, range 10/30 ft., one target. Hit: 1 force damage.
Marples are little glowy fish that float, and like both the air and water. They are cute little pets.