Ahh I didn't really specify how it works.
When the code for specific fish is activated (which you did correctly but partially - one at a time! You don't need Bass 0% for the other fish codes), it will change the entire world's spawn rate accordingly. Which means no matter what you do within that game instance, the spawn rate is supposed to be fixed and unchanged (even if you disable the cheat or enable another cheat). Therefore, what I generally do is I would completely quit the game (i.e. Press the Home button, close the game, and restart it) and enter the game again. This way, the spawn rate of all fishes return to normal.
Then, all you have to do is redo the process by enabling any of the fish codes.
TLDR:
1) Only enable 1 code at a time (including the 0% Bass spawn rate)
2) Close the game and restart the game
3) Enable another code
That should be the ideal way.
I hope I didn't misread what you said you've been doing - hope any of these helps too
Hi Herman925, thanks for coming back to me and the information. That makes perfect sense. I'll give it a try later when I get home. Thanks again