This ressource pack is very recommended for the datapack "All TropicalFish Datapack" who allows you to collect all variants of tropical fish.
It can helps you to visualise more precisiously each tropical fish variants via customs models and retexturing for all colors in advancement's menu.
With this ressource pack, collect them all is easy !
Global advancement tab
Flopper advancement tab
Datapack available on cursed forge "All Tropical Fish Datapack"