Water Breathing

Water Breathing is a status effect that prevents or delays drowning, and allows waterlogged beds to be used. , it additionally prevents or delays squid, glow squid, salmon, cod, pufferfish, tropical fish, nautilus, and tadpoles from taking suffocation damage when they are not in water, and also prevents players/mobs from taking suffocation damage inside full, solid, non-transparent blocks.

Causes

also gives the player a similar effect to Water Breathing (among other things).

Immune mobs

Withers and ender dragons are immune to Water Breathing. Aquatic mobs (except for the dolphin) are unaffected by water breathing and all undead mobs (except husks and zombies thus they convert into zombies and drowned) are unaffected by water breathing.