Fish drops from fish entities aren’t affected by the looting enchantment. They drop a fish and bone (25% chance) if without looting enchantment. But fish dropping doesn't increase when using looting enchantment.

Affects cod, salmon, tropical fish, and pufferfish

Steps to Reproduce:

1. Make sure to enchant your sword with Looting 3, using /enchant @s looting 3
2. Summon a cod, salmon, tropical fish, or pufferfish.
3. Kill it using the sword enchanted with looting and observe the loot that it drops upon death

Observed Results:

Fish drops aren't affected by the looting enchantment, but bone drops are.

Expected Results:

Fish drops would be affected by the looting enchantment.