Exercise for an old corydoras does not look like exercise for a midwater fish. This is a bottom dweller whose natural work is sifting sand, worrying food out of leaf litter and shuffling from patch to patch with its barbels reading the floor. Enrichment that suits it brings that work back in miniature, at floor level, in short bouts the fish chooses, rather than adding current to fight, heights to climb or puzzles hung where it will never go.
Turn the Evening Feed Into a Forage
Instead of placing the whole meal in one pile, scatter a portion of tiny foods, such as micro pellets, crushed wafer fragments or thawed morsels, thinly through the fish's favourite area shortly before lights dim. The corydoras then earns the same food through movement: nosing item after item out of the surface, pausing, breathing and moving on. Keep the scatter tight enough that the fish succeeds often, because a forage that yields nothing teaches it to stop trying. Feed the rest of the ration normally at first while you judge its enthusiasm, and widen the scatter gradually over evenings as its foraging confidence grows.
Build a Leaf-Litter Patch It Can Work
Lay a shallow patch of clean, aquarium-safe dried leaves over soft sand in a sheltered corner and refresh pieces as they soften and break down. Litter gives the floor texture and edges: food lodges under leaf margins, scent pools in the still layer above the sand, and the fish pushes, lifts and circles as it searches, using muscles that a bare, swept floor never asks for. Keep the patch modest in size so waste cannot accumulate unseen beneath deep layers, and siphon under the leaves during water changes. An old fish that spends its evening working one litter patch is doing exactly the low, steady activity its body was built for.
Let the Shoal Make Activity Social
Let it forage alongside its companions rather than alone. Corydoras feed more boldly and move more when familiar fish are working the same ground, and an elderly fish often follows a younger shoalmate to a spot it would not have visited by itself. Scatter enough food across the patch that company does not become competition, and watch that bolder fish do not strip the litter before the old fish arrives; if they do, start the old fish's corner scatter a minute earlier. Social foraging also gives you a comparison: a fish that keeps pace socially, even slowly, is coping better than one that has stopped joining the group at all.
Vary the Floor, Not the Whole Tank
Rotate interest within the bottom world the fish trusts. Move the litter patch between two or three familiar corners across the week, rest a smooth stone or low wood piece in a new position, or place the evening scatter along a short route between shelter and patch so the fish travels a little further for its reward. Change one element at a time and leave it in place for days, because an old fish navigates by memory and scent, and constant rearrangement turns enrichment into confusion. Never add strong flow, bright new lighting or tall structures as stimulation; novelty for this species lives in scent, texture and food placement, all within an inch of the sand.
Read Effort and Know When to Ease Off
A good session ends with the fish still interested: barbels active, breathing settling quickly after bouts, and a return to its shelter by choice rather than collapse into the first cover it reaches. Ease off if foraging becomes frantic, breathing stays rapid, or the fish abandons the patch immediately, and return to closer, simpler food placement for a few evenings. Losing interest in foraging it once enjoyed, refusing food at the resting area, or separating from the shoal are changes to act on: test the water, and contact an aquatic vet or specialist promptly if the shift is sudden, because disinterest in this fish is information, not stubbornness.
To keep scatter nights and litter refreshes from drifting, open KinsLe together and assign each small task under Care Teams, where the helper on duty sees tonight's corner without asking anyone.