Water change 2x a week, say 50%, dose ferts after.
Temp, might bump to 84F.
They seem gasping at the surface, never good, check rates of respiration/breathing etc. Oily slick at the surface also suggest something may be amiss(like too much cO2/not enough current/O2).
NEVER reduce the surface to nothing. That's no place for any fish, with or without plants.
A good ripple, but not enough to break the water's surface is a good rule of thumb.
This will allow more CO2 wiggle room since you will have more O2. Respiration is both CO2 and O2, so the more O2, the better. CO2 should be easier to add.
I use wet/drys for all my tanks for this reasons(more O2 than canister filtration).