The floor is the decor that matters most
For corydoras, furnishing starts from the ground up, because the ground is where they live. A cory's day is spent nose-down, shuffling along the substrate and pushing its barbels — the whiskery feelers around its mouth — into the surface to taste for food. Soft sand is therefore not an aesthetic preference but the species' working surface: they dig into it up to their eyes, sift it, and rest on it in a group. Cover the whole floor in a decent depth of smooth sand and the behaviour you bought corys for appears within the hour.
Sharp or coarse gravel is the classic cory mistake. Barbels dragging over rough, dirty gravel wear and erode. If gravel already fills the tank, adding a contained sand beach in one open area is a genuine improvement the group will adopt immediately — they will do their foraging and much of their resting on the patch you give them.
Layout: open middle, furnished edges
Arrange the tank as a beach with a furnished rim. Keep the front-centre sand open and empty — that is the stage where the group sweeps back and forth at feeding time, the single most charming sight in a cory tank. Push planting, wood, and stone to the back and sides, where they shelter without stealing the floor.
Shelter itself should be low and communal. Corys do not want individual caves; they rest shoulder to shoulder in loose groups under a shared roof. A broad piece of driftwood laid low, a wide flat leaf canopy near the floor, or a smooth stone overhang that shades a patch of sand all serve — the group will pick its favourite and pile in at midday. Provide two such spots so the shoal can split and regroup naturally rather than defending one address.
Plants for a digging fish
Plant the rim with species that tolerate life beside excavators. Sturdy rosette plants with strong roots hold their ground once established; plants attached to wood and stone bypass the substrate entirely and are the safest choice near the digging zones; floating plants add the dappled shade corys appreciate without touching the floor at all. Delicate stem plants planted straight into sand beside a busy cory group will be found floating most mornings — either anchor them deeply, ring their bases with stones, or move them to the quieter corners.
Keep planting out of the open beach. A stray plant in the middle becomes a tiny island the group circles, which is harmless, but a creeping carpet across the sand removes the digging surface that is the whole point of the layout.
Smoothness, and what to leave out
Run the same hand-check here as in any bottom-fish tank: decor edges, stone surfaces, and wood should be smooth, because cory bellies and barbels contact everything at floor level. Avoid sharp-edged rock, rough lava-style stone at ground level, and ornaments with narrow gaps at the base — a startled cory wedging into a tight crevice can scrape itself badly. Leaf litter scattered lightly over a back corner of the sand adds natural foraging texture and tiny food life, and the group will work through it happily.
Spend your effort on floor area and shade rather than tall ornaments and stacked rockwork, which give corys nothing.
Keeping the beach clean
A cory floor needs its own small routine: waste gathers beneath the low shelters the fish love, mulm collects at the sand's edge against the glass, and the open beach shows every speck — which is the tank telling you the truth about its housekeeping. Lift shelters occasionally during water changes, siphon under them, and smooth the sand back over the beach.
Those little floor jobs are precisely the ones that slip between helpers on a shared community tank, so KinsLe Care Teams lets you assign the sand and shelter checks for the corydoras with each completed task marked by a timestamp.