Hello! I don't have the best camera, but here are pics of what I'm describing. I can't find anywhere else online with this type of algae/critter being described, so I figured asking directly would help ^^ It grows on the side of the glass alongside the green algae that's been forming; any help identifying it and if it's harmful or not would be really appreciated.
One other thing... I had an outbreak of white fluffy mold that grew above water that must've started around June. I only figured out what was going on in August & removed the heater that the mold was growing in the crevices of, and put cleaning vinegar on the other areas of the glass that it was growing on multiple times. Despite this, their nitrates are still always clocking in around 30 no matter how many water changes I do and it worries me. Everything else is fine. All my opae ula seem to be completely normal and have been breeding a lot, which seems to suggest to me that everything's fine. They do seem to be a bit lethargic until I do a water change, to which they get excited and swim about, encircling the tank and galloping. Should I redo their tank? Put them in another container with fresh brackish water and just entirely redo their tank / get a new tank to house them in? I'm worried the effects of the mold might never go away for some reason, I've done gallons and gallons of water changes and wiped down the outside glass with cleaning vinegar to ensure its completely gone to no avail. The amount of nitrates I have always clocks in anywhere from 20 to 40. Nobody's died, either, and I haven't fed them in 3 months to cut down on how much nitrates go into the tank. They graze on the wall of algae just fine for nutrition. I've only kept them for a year insofar, does anyone have any advice or experience with these problems?
Thank you so much for reading all this!!