How can you tell iff catfish has gone bad?

the smell will be stronger even after rinsing and will be kind of slimey to the touch more than usual

I was filleting the catfish, when I noticed a couple spots on the meat, I cut it off, but I wanted to make sure it was normal? Does that mean the meat is bad?

Any fish that's gone bad will smell like a fish, and like the sea...a good and clean fish shouldn't have any smell at all, the eyes should be clear and the gills should be a bright good color. usually red or bright dark pink

I have been eating catfish nugget for years and my experience of good nuggets are they are pink in color and have no odor what so ever also not slimy

As above...it smells bad. I know fish have a characteristic "fishy" smell. If it goes bad it'll smell rotten.

Bad smell is a good indication.

if it starts to smell fishy its gone bad and if the eyes arent clear and when pressed with your finger its soft and there isnt any resist

Thats too easy!

First, they lie. steal, cheat, drinkin' and drugin'stay out late with their no good friends, you know the rest....

When they start using curse words and skipping school?

...if it smells funny or tastes funny dont eat it...trust ur senses.