A 50-gallon tiger barb tank, 36 inches long

[Nutty]

Can you show a real pic?

[tetraTim]

I'm not entirely convinced that tanks need a substrate. I've seen plenty of discus and monster fish keepers who get by just fine without one. That being said, I do think they have their benefits - especially for corys. I mean, if I'm being honest, I love corys and they're so much fun to watch in a group.

I'm not sure I agree that every fish needs a substrate, though. It's like everything else in this hobby - there are pros and cons to consider. I'm curious, OP, why do you want to swap out your corys for a bristlenose? Both are great fish, but you'll definitely get more movement out of a group of corys.