What makes an armored fish an armored fish?

[Drakmanka]

Maybe this is a dumb question, but hey, the dumbest question is the one you never ask, right?
I have a Banjo Catfish, and as I've been learning more about them as a species, the more questions I find myself asking about them, and armored fish in general.
What are the differences between an armored fish and a scaled fish?
Why are Banjo Catfish scaleless?
Can an armored fish also be a scaled fish?

Answers to any of the above questions would be awesome, thanks in advance!

 

[Stacey W.]

This is what I know armoured fish have bony plates that run down their body vs scales. If you take a good look at a corydora you can see them.

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