I would like to make the following suggestions:
[Forge 1.20.1]

• Configurable health
• Wearable armor (like horses, we can just use horse armor)
• Attachable chests (like mules)
• Natural regeneration (dunno if this is a bug, but they don't regenerate naturally)
• Heal-able by fish as well. Currently, only other meat can be used to heal them which is weird since they were tamed with fish to begin with

1. Health can be configured using datpacks. You can simply copy+paste the original json data and put the breed json in your own custom datapack which will override the mods breed, and you can tweak from there.

2. Wearable armor has been suggested a number of times. However, I will reiterate that this is not DM2, and armor is not planned for the main mod. That does not mean however that an addon is not out of the question for this.

3. See 2.

4. Sure, I actually never even thought of that, will add.

5. Meat heals, fish tames and breeds, for now it's gonna stay like that.

Closing as completed as I did take in one of the recommendations here.