The honest answer: nerites usually feed themselves
A nerite snail is a specialist grazer with a rasping tongue that scrapes soft green algae and biofilm from glass, stone, wood, and plant leaves almost continuously while it is awake. In a mature tank with lights on long enough to grow a light film, that grazing is a complete diet, and adding scheduled meals only pollutes the water the snail depends on. This is why experienced keepers warn against putting several nerites into a small, pristine tank: the snails do not starve dramatically, they simply run out of film, slow down, and decline while the glass looks beautifully clean. Feeding frequency, for nerites, is really a question about how much natural grazing your particular tank provides.
When a supplement two or three times a week is needed
Step in when the tank is new, heavily scrubbed, shared with competing algae eaters, or lit so briefly that surfaces stay bare. Two or three small offerings a week then keep a nerite in condition: a fingernail-sized fragment of algae wafer, a thin slice of blanched zucchini or green bean, or a smear of algae-based gel on a stone it frequents. Offer in the evening, when nerites are most active, and set the food touching or immediately beside the snail rather than across the tank, because a nerite navigates by slow exploration and may never find a wafer dropped behind the filter. Some individuals refuse wafers entirely yet accept blanched vegetables, so rotate the offering before concluding yours will not take supplements.
What nerites will not do for you
Do not expect a nerite to survive on fish leftovers, sinking pellets, or the hard green spot algae that dots old glass. Its mouth is adapted to soft films, and the tough spot algae usually remains untouched no matter how hungry the snail is, which is a limitation of the species rather than a feeding failure on your part. Nerites also need calcium available through the water and diet for shell maintenance, so in very soft water a supplement routine should sit alongside attention to mineral content, guided by test results rather than guesswork. A snail that stops moving for long stretches, fails to right itself, or shows a receding body at the shell opening needs a water check and prompt advice, not simply more food placed beside it.
Watching whether the routine is working
A feeding nerite leaves evidence: faint zigzag scrape trails through algae on the glass, steady nightly movement between surfaces, and, in females, small white sesame-like eggs dotted on wood and stone, which signal condition even though they will not hatch in fresh water. Weigh the routine by leftovers instead of enthusiasm. If the wafer fragment is untouched after a day, the tank is providing enough and you can stretch supplements to once a week or pause them; if it is stripped within hours and the glass carries no film at all, increase to every other day while you also ease back on glass scraping and leave the back panel deliberately uncleaned as a grazing reserve.
A light-touch record for a light-touch feeder
Because nerite feeding is occasional and conditional, it is the first task forgotten after a tank clean, precisely when the freshly scrubbed glass offers the least to graze. A brief note after each deep clean, recording that supplements resume until algae returns, closes that gap. KinsLe Care Teams fits that pattern well, carrying a simple recurring reminder for the snail supplement that any helper can mark done with a timestamp once the wafer is placed.