It's more likely to be the other platies eating your fry than the loach.
This is what I'd buy if you want fry.
5 gallon container - $10
Heater - $15
Cheap fake plant and bark tunnel - $10
Air pump - $15
Corner filter - $8
Total - Around $60. In my opinion, every aquarist should have these items anyway. It's just common sense to have a few backups. If I hadn't had this cheap spare equipment when things went wrong I'd have lost a lot of fish. Shove the junk in the container and stick the whole lot in the cupboard the rest of the time.
When your female is really pregnant and within a few days of giving birth, set up the container. Get a little plastic food container as well and fill it with gravel. (Fry hiding place.) Put the female in the tank. Use a lid, they sometimes jump.
This is a lot safer than little plastic breeding traps. They are fish killers. If your female doesn't die of stress (this is quite common, it sends them crazy) she may abort the fry and you'll lose the whole lot. You can use them for raising very small fry in the main tank and that's really all they're good for unless you catch the fish the moment she starts giving birth and save the fry and then put her straight back in the tank.
When she's had the fry (is no longer fat like she's swallowed a golf ball) put her back in the tank. Then raise the fry.