OK,here goes

I think minecraft should add more fish with different type of items dropped each time we fish ill explain later
also more fishing rod like diamond rod which catch rarer fish and if not will catch more fish like 10 per swing in expense of a handful of uses only
caught fish cannot be eaten instantly but have to be skinned on a crafting bench.the fish also have its own skin and shape underwater to represent its type with colored font to display its rarity
The Fishing Rod
For the fishing rod simply put a fishing rod in the middle with an ore(no coal,and flint)below it.The higher the item the more to obtain rare fish.diamond will have like 50% to obtain one while emerald will have 80% as for the other ores will range from 1%-10%
Tackle Box
A tackle box for baits,simply put a wood in the crafting bench to obtain one.it holds 2 extra rod and a good amount of bait.tackle box can be put like a chest on a bot but will not de-mount the player
Baits
For the bait you can use seeds,worms(obtained through dirt by right clicking it with empty hand or a shovel) and other foods at your disposal.to equip the bait right click the tackle box to equip the bait until you got the preferred bait.type of bait will not affect your fish also if you throw a bait into a sea a shoal of fish will gather for a period of time depends on the food like bread will hold for 1-2 minutes(golden apple are too hard for the fishes).type of bait affect the type of fish.no stews.non-colored means no rare fish even with diamond and emerald rod.
the common fishes look like a normal fish(white font)=give raw fish only
the uncommon is a little bit longer than normal(yellow font)=give raw fish and a few scales
the highly uncommon is pretty small(blue font)=gives raw fish with buff effects but no scales
the rare will have the enchanted glow on it(pink font)=give raw fish with buff efffects and chance of gold nugget when skinned
the legendary will have enchanted glow and particles around it(purple font)=gives raw fish with a chance of diamond
Those are the non-hostile fish here are the hostile ones.(meat as a bait)
Puffer fish will poison the player unless touched because it will not jump into your inventory.it gives you poisonous prickle(5 prickle) when skinned which can be use as arrows tip.
Lastly,the arowana will jump into the players inventory,damages the player by 2 hearts.gives you arowana's bane which can be used as a sword upgrade or a bow's
The armor is as strong as leather and it will gives you:
Respiration,Aqua Affinity and walk fast underwater
but on the ground the player will get slowness
The poisonous prickle as an arrow tip will poison a mob
The bane will only give the weapon slowness enchant so the mob will walk slowly(simply put the bane below the weapon in the crafting bench)

Wheats will catch uncommon fish. Bread will catch very uncommon fish. Carrots will catch highly uncommon fish Pumpkin will catch all of the fish type but no rare(depends) Sugar will catch highly uncommon fish and also a lil bit of luck with rare fish. Apple will catch rare fish with a bit of legendary Golden Apple(i lied XD) will grab legendary fish

To skin a fish you have to craft a knife(can be thrown and attack mobs)the recipe is like a sword but one stick short and one ore on top.once you got it,put a knife and a fish inside a crafting bench,now you have a raw fish and a few scales for an armor.other items will drop on the crafting bench like eg diamond.

The Fishes

When you throw a food,you can see what type of fish gather but cannot hit it.when you see a rare fish,your chance of getting it depends on what you use.

Piranha will continuously damage the player by a quarter of hearts but always come in a group of five.When pulled,it will go straight into the players inventory.so the player must skin it fast or throw it.when skinned,it will give you teeth which can be crafted as a weapon.

The equipment

For the armor,you have to craft yourself a scale+ by putting 9 scale inside a crafting bench.once you got it,you can craft the armor as usual.

The weapons

Teeth knife(same recipe as knife but using the piranha's teeth)will do 3 hearts damage with smite lv 3

Some of the buff effects

Will be strength,swiftness,defense,regenaration,night vision and also invisibilty

Oh and btw

When you cook a fish the effect will not change.Psstt,the diamond and emerald rod will damage the player by half a heart but as i say only for a handful of uses only.(for those who got ambush by other player)

PM or comment me if there's anything I can help.:))