We are fairly new fishkeepers, about half a year now. In the last months we got four platys in total, only two are alive. Also three guppies, only one alive.
Story of the platys:
First two were bought, a male and a female (didn't realise til home). Female was weird from the beginning, constantly circling the starfish ornament, male one was behind her every now and then. After a couple of weeks she died. We were not sure whether she was just weird or if it was because the male chased her every now and then so upon advice of the pet shop we got two females to go with the male (so that's the second two bought a few weeks later).
One female straight got friendly with our male one, he doesn't chase her and they are just happily swimming together. The other female hid behind / in between the live plants from the beginning. We barely saw her, she didn't even come out for feeding times. One week later - dead.
So, out of four we have one living pair which seems very happy, they swim around the whole tank and just seem contempt.
Story of the guppies:
Bought two male ones. One died after a week. Replaced with another one weeks later, that died within two days! First one still happily swimming around, joining the platys in their adventures around the tank.
I am now wondering, is it pot luck if you get 'good' fish? Water is good, we check it every week for nitrites and ph. All fish came from the same local pet shop (not PaH, hate them). The ones still alive are happy fish. Is it really sometimes hit and miss and you could just end up with ones that don't cope with the whole 'new tank, new environment' scenario or are already weak?