Cooked Cod

Raw cod is a food item. Cooked cod is a food item obtained by cooking raw cod.

Fishing
The most common way of obtaining raw cod is fishing. The wait time of one being caught is decreased with the Lure enchantment and the chance of one being caught is slightly decreased with the Luck of the Sea enchantment (named as such because it increases treasure, not fish).

Guardians and Elder Guardians
Guardians and elder guardians have a 40% and 50% chance to drop raw cod as a common drop respectively when killed. The raw cod will become cooked if the guardian/elder guardian was killed while on fire.

Guardians and elder guardians also drop a random fish as a rare drop besides the common raw cod drop. This has a 60% chance of being raw cod. The chance of getting a fish can be increased with Looting, but the type of fish is not affected.

Polar Bears
Polar bears drop 0–2 raw cod when killed. This has a 75% chance of being raw cod and a 25% chance of being raw salmon. The cod and/or salmon will be raw even if the polar bear is on fire when killed.

Cod mobs
Cod mobs will always drop 1 raw cod when killed. If it is killed on fire, it will drop cooked cod instead.

Dolphins
Dolphins drop 0–1 raw cod when killed, with the chance for an additional cod per level of looting used.

Trading
Fisherman villagers will sell 6 cooked cod for 6 raw cod and 1 emerald.

Food
Raw cod restores and 0.4 saturation. Cooked fish restores / and 0.6/6 saturation.

Ocelots
Raw cod can be used to tame ocelots, get cats off of chests, beds, etc., breed cats, and make baby cats grow up faster by 10% of the remaining time.

Dolphins
Dolphins can be fed raw cod. Doing this will improve their trust with the player, and interact with them more. However, unlike most animals, this will not cause them to breed.

Additionally, dolphins will swim to the nearest chest in an underwater ruins or shipwreck structure when they are fed raw cod. If the chest in the nearest structure is broken, they will instead swim to the nearest structure that has a chest.

Trivia

 * In the Halloween Update, Notch said he would add fish as a sea creature; however, he had limited time, and was thus only able to add them as an item. However, they will be added in 1.13 update.
 * Raw fish most closely resembles white crappie or tilapia. However, the texture files and language text label them as cod. In 1.13, its in-game name will be cod as well.