they are alone, but i have experience with platies being eaten.
in my 20 i thought i few would survive but i was wrong. i had lots of plants and hiding spots.
i was wrong. the third batch i managed to save one. i quickly set up a 1.5 gallon tank. i had a filter rated for 3 gallons. i took some media from my 20 gallon and put it in it and had some gravel too with a small plastic plant. also had a mini betta heater. 1 month later probably a few days before i could introduce it into the main tank it got sucked up into the filter during the night and didn't make it. i was so sad. ready to change that outcome this time