That dorsal fin trailer is amazing. Very nice fishies!
It looks like you might have a little bit of fin clamping going on. Might be a good idea to upgrade the filtration and/or do more water changes. But I'd recommend adding powerheads too so there's some current and they have to exercise the fins instead of just being able to chill.
I know my Angels and Achara will clamp fins when my powerhead gets clogged. No current, why bother?