Saes?Sae's are a good choice to get rid of that algae also aside from snails and occasionally mollies. If you are thinking of a new fish to add I would get at least 4 of them. They keep my 90 bba free. They are fast swimmers and are a bit suicidal when it comes to jumping though so make sure your lid is tight and any gaps are tiny.
This reminds me, I should replace the t8 bulb on my 20, I've had it for like 3 years. I should check my t5's too.