Crazy catfish

[Susanna]

I have a fully planted 30l tank everything is going well I had 1 casualty earlier on when one of my neons decided to evolve into a terrestrial creature which didn't go well!
I have shrimps breeding

but I seem to have a crazy salt and pepper corydorus the smaller is as good as gold keeps himself to himself doing fishy things at the bottom but the other keeps diving ? from the bottom to the top for no reason that i can see hes not after the baby shrimps.

Is this normal behaviour or has he banged his head too much ? Any suggestions?

 

[Hufsa]

Gulping air

 

[Susanna]

none of my other fish are doing this that's why its odd

 

[jameson_uk]

Normal behaviour for corys
https://www.practicalfishkeeping.co.uk/features/why-do-corydoras-take-gulps-from-the-surface/