Innate Spellcasting: the nixie's spellcasting ability is Charisma (spell save DC 14, +6 to hit with spell attacks). The nixie can innately cast the following spells, requiring no material components:
Amphibious: The nixie can breathe air and water.
Dagger: Melee or Ranged Weapon Attack: +5 to hit, reach 5 ft, or range 20/60 ft, one target. Hit: 5 1d4+3 piercing damage. Summon Swarm of Fish (1/Day): The nixie can summon a swarm of harmless fish, which arrives in 1 round. As a bonus action the nixie can command the swarm to distract a target 9forcing it to make all attacks at disadvantage) or to surround the nixie (providing half cover). The swarm dissipates after 10 rounds, or as soon as it suffers damage.