There is so much content in your game ! 108 fish types, I couldn't catch them all.
The art was very nice. Good music and SFX.
You don't get any information when your inventory is full so I didn't know why fishes stopped appearing, that confused me. There is also a bug : looks like the upgrade prices reset each time you leave the shop. I think there are many possible little QoL improvements, but it doesn't affect the fun a lot.
One visual thing very easy to fix was the font border. Instead of only copying the text one time with the border color with x+1 & y+1 offset, you should also do it a second time with x+1 & y+0 and a third time with x+0 & y+1. That will avoid the little weird-looking edges on the text.
But apart of these minor problems, the game was really enjoyable, even if it was way too long for a jam.