I had been keeping the algae under control relatively well, and I had only the whitish algae, which I wiped up no problem.
I posted a picture a few weeks ago of the algae I found in my filter, but I wasn't too worried - I picked up sponges to use instead of a carbon cartridge.
Then I went out of town and came back to a tank that was SWIMMING in blue-green algae! At first I wasn't sure what was wrong, and Nero was NQR - had cloudy eyes and green spots on his gills. After help from OFL (if you read this, thank you again!!), the reason was pinpointed to the algae. It had somehow gotten out of control while my dad was in charge of the tank.
So yesterday I cupped Nero, drained the tank completely, yanked out the fake plants (they had long strips of the algae caught on them), took out the filter cartridge and threw it out, scrubbed the tank with hot water, cleaned the filter itself with Q-tips. I also scrubbed the tank equipment and decor (thermometer, heater, and cave) in hot water.
I wasn't sure if it was necessary, but I got a marimo moss ball to help with water quality - it might be able to keep any algae under control.
Nero still doesn't look quite right, but I'm hoping clean water, frequent water changes, and TLC will help him.
Did I take all the necessary steps, considering the algae is essentially a bacteria and could come back any time?