Avoid trying to fix problems you (nor anyone else) are not sure of. Don't start throwing shit on it hoping something sticks.
If it were mine I would let it dry out really well, even to the point of wilting. Wilting is not a bad thing, they will suck up everything at that point. Your soil looks really dark and wet but maybe you just watered.
Let the thing go a few days,where the leaves might even begin to droop, then soak it with 1/4 - 1/2 concentration of ferts.
Actually looks a bit N starved, which is easy to overcome.
Let it dry, dry and dry some more. Let the soil get bone dry before you water.