Hi,
what you could do is to buy live boons from the LFS, use the boon net to filter them out, put small portion per feeding into the ice cube container and use existing tank water to freeze them.
By doing so, you do small feeding and dun foul the water and the filter. This method is very effective for raising fries and all will grow up fast.
dun use the boon water to freeze as its is salt water, use existing tank water.