The short answer for an adult corydoras
One main meal a day is the usual pattern for a healthy adult corydoras catfish. A cory is a bottom-feeding scavenger by habit, not a fish that needs food scattered through the whole day, and its small stomach suits a single proper feeding far better than constant nibbles of rich food. Some keepers split that same daily amount into a morning portion and a smaller evening portion, which is also fine for an active group. What matters for an adult corydoras is the total that reaches the bottom in a day, not how impressive the feeding looks from above the glass.
Why corydoras miss meals in community tanks
An adult corydoras often misses food because faster mid-water fish intercept flakes and floating pellets before anything sinks. The corydoras group then roots hopefully through the substrate while the actual nutrition has already been eaten above them, so a tank can look well fed while the corys are quietly underfed. The reverse problem happens when a worried keeper drops extra wafers late at night to compensate. Those wafers soften, break apart, and foul the sand if the group is already full. Judging an adult corydoras meal by what the whole tank received is unreliable; judge it by what the whiskered fish on the bottom actually ate.
How to serve the corydoras meal so it lands
Serve the adult corydoras meal as sinking pellets, a small wafer broken for the group, or thawed frozen food that drops straight down. Feed the upper levels first, wait a moment, then place the cory food in an open patch of substrate where you can see the group gather and work over it. Evening feeding suits corydoras well because they grow bolder as light fades and will forage in a loose shoal. Give only what the group finishes while actively nosing the bottom, and lift out any pellet that sits untouched and mushy afterward. Rotate protein-rich sinking foods with a vegetable-based option so the adult corydoras diet is not built on a single wafer.
Signs the corydoras schedule needs adjusting
An adult corydoras on the right schedule stays rounded without looking swollen, keeps its barbels intact, and comes out promptly when food lands. Thin flanks, frantic scavenging long after feeding, or a group that hides through its usual meal all suggest the corydoras are getting less than the tank appears to offer. Cloudy water, food decaying in the sand, and corys surfacing repeatedly point the other way, toward too much sinking food sitting too long. Change the amount before you change the frequency, because one well-judged adult corydoras meal beats two generous ones. If a corydoras stops eating, loses weight steadily, or shows damaged barbels, contact a veterinarian familiar with fish rather than simply adding richer food.
Keeping the bottom feeding from being doubled
The classic adult corydoras mistake is a second keeper dropping a wafer because the first feeding left no visible trace on the surface. A note that names the time, the food, and where on the substrate it was placed ends that guesswork for the whole household. It also helps to record which days the group got frozen food, so variety does not accidentally become three rich days in a row. For a shared tank, KinsLe Care Teams lets the person who fed the corydoras log that bottom meal as done, keeping the next helper from serving a duplicate wafer.