I have a female german blue ram that came from the pet store so is probably not of the most sturdy stock to begin with. She is in a 20 gallon long with five cardinal tetras (there'll be more eventually) and one albino cory*. There's currently an Aquaclear 50 HOB and a sponge filter rated for 40 gallons running in the tank (so I can jump start my quarantine tank once I get more cardinals). Temperature is set to 81F with +/-1 on inkbird (so, range of 80-82F). It's been this temperature range for the past two months that I've had her. Tank is moderately planted with three arches and a cave to hide in/under.
Saturday, I removed and re-homed 6 black skirt tetras because they were bullying everyone and hogging all of the food. The decor did shift slightly as a result, and I did a water change at the same time. Water parameters taken this morning are 0 ammonia, 0 nitrites, 5 nitrates, pH 7 (this is stable and consistent). Water parameters before the water change were 0, 0, 10-20 (stupid API tests looking the same). I've never let the nitrates get above 20, test weekly, water change weekly.
She's been glass surfing since Saturday and her pink belly is fading, although the rest of her color looks normal. She's still eating. This is a new behavior.
I'm not sure if she's glass surfing because of the water change/slight shift in environment, or if there's something else going on, but it's sad to watch her so stressed out. Does anyone have any ideas?
*This is a long story. I know there should be six of them, basically this is the only survivor of a total of 12 albino corys from the pet store in one very frustrating and sad bad batch from their supplier. Even the fish person at the store said they're having problems with that supplier and she's trying to find a new one. I'm kind of waiting and seeing with the albino before I buy more or decide to rehome him. I know they max out around 80 so the temperature isn't the best match with a GBR. But this guy is why I don't want to raise the temperature more than it is.