Platies and mollies give their young a head start: both are livebearers, and their fry are born comparatively large, free-swimming, and able to tackle ordinary foods ground small. Caring for them well is less about specialist fry rations and more about three things — not being eaten in the first days, having genuine room to grow, and water and food that reflect what these fish are: hardy grazers with a real appetite for plant matter.
Shelter first, because the parents are grazers too
Adult platies and mollies browse constantly, and newborn fry are part of what they find. Provide dense fine-leaved planting, floating cover, or a moss thicket before a female drops her young, and many fry will survive in the community tank without any rescue work. For a deliberate batch, move the fry to a rearing tank rather than holding them long in a small breeder box; molly fry in particular grow quickly and sulk in cramped boxes. A sponge filter keeps the rearing water moving without endangering small fish, and water drawn from the parents' tank avoids any shock of new conditions on day one. Scoop fry across in water, in a cup, rather than lifting them in a net.
Feed like the adults, only smaller and greener
Crushed flake or powdered fry food suits both species from the start, offered in small amounts several times a day and eaten within a couple of minutes. What marks platy and molly fry out from many others is the vegetable side of the menu: finely crumbled algae-based foods, a little blanched and softened green vegetable matter offered in tiny pieces, and access to soft algae growth on plants and glass all support the grazing habit they are born with. Baby brine shrimp or similar small protein foods a few times a week round out growth. Watch bellies rather than schedules — rounded but not swollen is right — and siphon away whatever settles uneaten, because a rearing tank fed four times a day fouls faster than its size suggests.
Water that matches what these livebearers like
Platies and mollies do best in water that is not soft and acidic, so raise the fry in the same water the parents thrive in rather than improvising a special fry mix. Mollies are the fussier of the two about water quality as they grow, and youngsters raised in a small, under-changed tank are prone to stunting and shimmying behaviour that signals conditions, not character. Small, frequent water changes with dechlorinated water matched for temperature are the backbone of fry care here: a modest portion every day or two in a rearing setup, with the siphon bucket checked for stray fry before it is emptied. Keep filtration gentle but real, and the temperature steady.
Space, sorting, and the next generation
Give the batch room. A rearing tank that feels generous in week one can be crowded by week six, and growth slows across the whole group when it is, so plan the youngsters' next home early — back to the main tank once they are too big for its largest mouth, or onward to new homes. Males and females become distinguishable as the anal fin shape develops, typically within the first couple of months, and separating them at that stage prevents the fry tank quietly producing its own fry. Seek aquatic advice if youngsters develop persistent shimmying, white spots, or stop growing despite clean water and good food. Keeping the batch's hatch date, foods, and water-change routine on the shared profile through KinsLe's Family Sharing means a partner or older child stepping in feeds the fry the same way you do.