Blazes don't naturally swim upwards in water or lava

The bug

When not aggravated, blazes will sink to the bottom of water or lava instead of floating at the surface like most non-undead mobs. They are still able to fly upwards if hostile.

To reproduce

Spawn a blaze in water or lava while in Creative mode.

Code analysis

This appears to be because blazes don't add a FloatGoal in net.minecraft.world.entity.monster.Blaze.registerGoals(), unlike most non-undead mobs.