I can’t say I see much algae outside of a bit of a film on the glass, which is to be expected in all tanks.
What are the exact parameters, and how often do you clean the tank?
What is the stocking? All I see is what looks like a juvie Vieja cichlid.
Parameters are important because certain types will thrive of certain params, and you may not notice something that is off.
Likely just diatoms, which are easy to just wipe off and make that part of routine maintenance, having an algae magnet helps a lot.
Live plants also help to steal nutrients from algae, but this doesn’t work with every fish.