I have a 72l tank with a few fish including 3 platies (initially - got them mid February)
It was 2 females and a male and they had babies - we currently have 5 of various sizes some of which I have moved to a different tank
The male platy suddenly started acting unwell, not swimming, lethargic and so on. We moved him to a different tank to try and treat but it was too late ☹️
Now one of the female platies is acting similar way, hiding a lot, not very interested in food. The other female platy is very energetic and still eating (possibly a bit frantic - appears to be surfing up and down the side of tank as in photo)
Have tested the water and it's within normal levels, the ph a bit high. The other fish (minnows, rasboras, barbs) and shrimp appear fine
Not sure what the issue is and am fairly new to this - any advice?