When condions are right- good water and enough food- they will be like this all the time. Within a week of hatching they will molt and you'll have another batch on the way. If you get over run, which will happen in a matter of a month or so, cut way down on the feeding.
i dont actually feed mine anymore than move plants from other tanks in to their tank for a clean up
i have other tanks so i dont think i will be over run for sometime