Fishing report via pond (1 hour):
Fishing Level: 879-881
I didn't count the EXP I had on me, and didn't realize I'd forgotten about that until I was nearly 30 minutes in to that, so... I'm leaving that out.

Fish: 300 @ $20 = $6000
Salmon: 80 @ $30 = $2400
Puffer: 55 @ $40 = $2200
Clown: 10 @ $50 = $500
Total: $11,100

Iron Helm: 10 @ $0.75 = $7.50
Iron Chest: 2 @ $0.75 = $1.50
Iron Pants: 11 @ $0.75 = $8.25
Iron Shoes: 8 @ $0.75 = $6

Iron Pick: 6 @ $0.75 = $4.50
Iron Axe: 0
Iron Shovel: 2 @ $0.75 = $1.50
Iron Hoe: 4 @ $0.75 = $3
Iron Sword: 2 @ $0.75 = $1.50
Bows: 2
Total: $33.75

Ghast Tear: 30 @ $10 = $300
Ender Pearl: 13 @ $3 = $39
Blaze Rod: 3 @ $1 = $3
Iron Ingot: 1 @ $7.50 = $7.50
Gold Ingot: 7 @ $10 = $70
Lapis Shard: 3 @ $3.75 = $11.25
Total: $430.75

Grand Total: $11,564.50

Enchanted Items:
Bow (Power2)
Iron Chest (Prot1, Fire Prot1, UNB1, Thorns1)

 

I’m going to do one with a low fishing level. :)

 

I did a bit of testing and research and learned the following
In vanilla when you catch a fish you get 1-6 xp
I caught several fish at level 318 which is rank 3/8 in /fishing and I got either 3, 6, 9, 12, 15, or 18 xp. What this means is I was getting 3x normal xp
I then had XxEddie_MinionxX fish at level 13 which is rank 1/8. He got 1, 2, 3, 4, 5, or 6 which is 1x normal.
I also had stevenjr05 test who's a rank 2 and he was getting multiples of 2.

I was unable to get anyone of a higher rank to test for me at the time but if the pattern continues it would suggest that at the highest rank which is 8 at level 875 or higher would give 8x the exp that a person at level 0 would get.

**EDIT**"
I tested with a rank 5 and a rank 7 and I leveled up to rank 4 so I now have results for those, it's not what was expected

At rank 4 I continued receiving 3x the normal amount.
At rank 5 the user began receiving 4x the normal amount.
At rank 7 the user received 5x the normal amount.

I also noticed that @strongpelt at level 1000+ which would be at max rank, received multiples of 5 in both of the test that were done. This suggests the following

Rank 1 (Levels 0-124): 1, 2, 3, 4, 5, or 6 xp
Rank 2 (Levels 125-249): 2, 4, 6, 8, 10, or 12 xp
Rank 3 (Levels 250-374): 3, 6, 9, 12, 15, or 18 xp
Rank 4 (Levels 375-499): 3, 6, 9, 12, 15, or 18 xp
Rank 5 (Levels 500-624): 4, 8, 12, 16, 20, or 24 xp
Rank 6 (Levels 625-799):
Rank 7 (Levels 800-874): 5, 10, 15, 20, 25, or 30 xp
Rank 8 (Levels 875+): 5, 10, 15, 20, 25, or 30 xp