Female platy fish staying at bottom of the tank?

Totally new to looking after fish, we just bought two female platys yesterday and all they seemed to do was hang around on the bottom of our tank, the red platy has decided to come out but constantly swimming near the surface whilst the yellowish one is staying at the bottom always hidden behind the plant, they both seem uninterested in food they ate yesterday when we brought them home but not now. Our tank is 25L, the tank was fully prepped out before the two platys went in with filter boost, tap safe, heater, filter, temperature was 26 Celsius (recommendation to us by Pets at Home was between 24c and 27c) my partner has been testing the tank yesterday and today with the brand ‘love fish’ testing strips for Ammonia, Nitrate, Nitrite, pH, Water Hardness (KH & GH) which have been fine which was confirmed by the shop. The tank are plenty of decorations in so hopefully shouldn’t be too bored, so we’re puzzled as to what’s going off?

Hi! Did you cycle your tank before adding fish? Please read on the Aquarium nitrogen cycle and how to cycle your tank. It normally takes weeks to get it cycled. I would do a 75% water change right now and see if that helps. Then do your reading. If the tank didn’t get cycled then your fish could be swimming in toxins such as ammonia, nitrite, and nitrates. We’re here to help.

Hi and welcome to the forum

The water looks milky cloudy, which is usually caused by uneaten food rotting in the tank. This can cause ammonia problems and stress the fish.

Try doing a 75% water change and gravel clean the substrate every day for the next 2 weeks. Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Monitor the ammonia and nitrite levels and do a 75% water change any day you have an ammonia or nitrite reading above 0, or a nitrate reading above 20ppm.

BTW, The red fish looks male.