Shawn P. Good wrote:
Hello :


I recently had a case of ICH in my planted community tank so I medicated for
a week and cranked the temp up to 86F to speed up the ICH cycle. Seems like
I was successful - no more signs of ICH going on 2 weeks now.

However, this happened the week before we went away on vacation. I had my
neighbour feeding my fish, and I showed him how much to give them each day.
I also forgot to lower the temp before I left so it stayed at 86F for the
week I was gone. However, when I got back last weekend, the tank walls were
covered in algae that was growth in perfectly round little circles. My 2
plecos didn't seem to be touching it. The day I got back, I took a scrub
brush to the inside of the tank walls, and it was almost impossible to scrub
that algae off the glass (actually, acrylic). It took alot of muscle power
to finally get it off.

This sounds like standard green spot algae. A much easier way to get it
off the tank walls is to use a scraper (plastic one since your tank is
acrylic). A cheap way that I've heard is to use an old credit card, but
I've never used this. I bought a small (approx 3" wide) plastic scraper
made for fish tanks for under $5US. It takes me usually just an up and
down pass with the scraper to remove the spot algae, much faster than
trying to scrub it off with the acrylic algae pads.

I've found this type of algae to be quite common in my rift lake tanks. It
doesn't seem to hurt the growth of the crypts and java fern any, so I just
scrape it off the front every month or so to maintain visual clarity. My
tap water is just teeming with fertilizers from agricultural runoff, so
algae is inevitable in my tanks. I'd prefer the green spot algae on the
sides to beard/brush algae. I have to wonder given the sudden appearance
of this algae if your neighbor may have overfed your fish, leading to
excessive nutrients in the water. Humans sometimes have that "kill them
with kindness" tendancy that leads to novices with fish adding way too
much food.