I have a 29 gallon planted community tank that is having some deaths. Current occupants are about 8 baby-teenager platys, 3 guppies, 1 molly, and 6 dwarf corys, and one ghost shrimp.
Water parameters are ammonia and nitrites 0, nitrates 10, pH7.6, gh is the darkest purple on the strip because texas, kh 120, chlorine 0.
A few weeks ago I lost an adult platy. I noticed it was being chased around a bit one day, then found him passed the next. Then in the last 2 days I have lost 2 platys and a guppy. All were noted to be lethargic for about a day, then swimming poorly and passing within 24 hours. I also feel like some of them were getting skinnier recently, but attributed that to them just no longer constantly reproducing. No obvious external symptoms (sores, fungus, etc)
Most recent additions have been the 6 corys but they all seem well.
I started a round of general cure yesterday, but wanted to make sure I wasnt missing anything else. Attached are pics and video of my poor guppy that seemed happy 48 hours ago and passed this morning.