Cardinals need help please!

[scubaboy]

I have been battling a bacterial infection with my YT in the display for the last month and thought I was past it as she is now back to normal and tomorrow I was going to do a water change to clean up the Kanaplex I have in the system.
All other fish have been fine up until just now I find my two cardinals in the corner on the bottom. Any idea what this could be?????

 

[vetteguy53081]

Increase oxygen via air stone and I’d feel safer treating with ruby rally reef
Are fish occasionally squabbling by chance?

 

[scubaboy]

Not until today, they have been a little. I have had my skimmer cup removed to provide additional oxygen. i will do a large WC today to see if that helps.

Do you think its just low O2 from the antibiotics?