I hope this works- I don't know if I've posted this picture correctly. But, if I did, it's the fish on the very top. Doesn't look much different from the rest, but you can see it's colors look a bit faded. It just never brightened up like the rest.
I haven't actually tested the pH in a bit, but it was staying at around 6.8 when I was testing that regularly. I've got 2 pieces of
driftwood in the tank to keep pH low.
And, no, no airstone. I've got quite a few plants in there, so I thought they would be enough for oxygen and that an airstone would just cause the CO2 to escape. Do you think an airstone would help?