A corydoras is a bottom pet, so children sit low
A corydoras catfish is best met at floor level, and teaching a child to sit beside the tank rather than loom over it changes everything. Corys spend their day on the substrate, shuffling along in a loose group and pausing to dig their faces into soft sand. From above, a child sees backs; from the side at their height, a child sees the whole performance, including the famous cory blink, when the eyes roll briefly downward. There is never a reason to lift one out for a closer look. Corys have sharp spines in their fins that can catch in a net and sting a hand, so the kind rule is simple: corys stay in their water, and children stay on their side of the glass.
Barbels explain why the bottom must stay gentle
The whiskers around a corydoras catfish's mouth are tasting tools, not decoration, and children who understand that treat the tank floor differently. A cory drags its barbels across the sand to find food, so sharp gravel, rough ornaments dragged around during a child's rearranging, and sudden digging in the substrate all work against the fish. Tapping matters here too: a shoal resting together will scatter at a knock, and fish that are startled repeatedly stop foraging in the open and hide behind plants instead. Teach your child that a group spread calmly across the sand, noses down, is a cory group that feels safe, and that their quiet behaviour is what keeps it that way.
Reading the group gives children a real role
A corydoras catfish should almost never be alone, so give your child the group count as their standing job. Corys are shoaling fish that rest, travel, and feed together, and a child can learn to check that the whole group has come out when food sinks to the bottom. Occasionally one cory will dash to the surface for a gulp of air, which is normal cory behaviour and a fun thing to spot first, not a sign of trouble to shout about. If one fish repeatedly sits apart, stops joining the evening forage, or its barbels look short and worn, the child's report to an adult genuinely matters, because bottom fish hide decline until it is advanced.
Feeding time, handled kindly
Feeding a corydoras catfish is where children most often go wrong with kindness, because the fish look busy and hungry. Corys are not fed by scattering flakes from above; their food must actually reach the floor, in a modest amount an adult measures, placed gently rather than poured in a cloud. A child can be the spotter who confirms the food landed where the group can find it, and the timer who notices leftovers still sitting there later, since uneaten food rotting in the sand fouls the water the barbels must taste through. Also teach children to wash and dry their hands before and after any supervised tank-side job, keeping soap residue well away from the water itself. Put the cory group's count, feeding spot, and no-net rule on their shared profile in KinsLe Family Sharing, and any adult supervising tank time will run it the same way.