A good corydoras brief starts with one fact your feeder probably does not know: these little catfish earn their living on the tank floor. Flake sprinkled on the surface may never reach them, especially if faster tankmates are overhead, so the whole briefing should be built around food that sinks, portions that cannot creep upward, and a quick daily look at how the group is behaving on the gravel.
Portion the sinking food before you leave
Corydoras need their own ration, not leftovers. Set out one small container per day holding the sinking pellets or wafers you normally drop in, and tell the feeder to tip in exactly one container, ideally in the evening when corydoras grow more active. Pre-portioning matters more for this species than for most, because a kind visitor who sees whiskered faces gathered at the glass tends to add a second helping, and uneaten food rotting in the substrate is what fouls a holiday tank. Write on the note that an empty container means the job is done, however pleading the fish look.
Show them what normal corydoras behavior looks like
A feeder who has never kept corydoras can misread the tank in both directions. Explain that healthy fish spend long spells resting together on the bottom, then burst into busy snuffling through the gravel, whiskers working, and occasionally dart to the surface for a gulp of air. That surface dash is normal corydoras behavior, not distress. What should prompt a phone call to you is different: several fish sitting clamped and motionless through a whole visit, rapid breathing that does not settle, or barbels that look worn down, since eroded whiskers can signal poor conditions at the substrate where these fish live.
Keep the equipment checks to two
Corydoras are hardy about many things but unforgiving of a stalled filter, because waste collects fastest at their level of the tank. Ask the feeder to confirm the filter outlet is moving the surface and the heater light cycles as usual, and to glance at the thermometer you have marked with the normal range. Leave a jug of dechlorinated water topped up beside the tank purely for evaporation top-ups, and be explicit that no water change is needed during a short trip unless you direct one by phone. Simplicity protects the fish better than an ambitious maintenance list in untrained hands.
Leave an emergency line that fits this species
Corydoras react badly to sudden changes, so your emergency instruction should be calm and narrow: if a fish dies, the feeder nets it out, feeds nothing that day, and calls you rather than improvising with the bottles under the tank. Note where your test kit lives only if the feeder is genuinely comfortable using it, and give the number of your usual aquatic shop as a second voice. One dead fish in a group is sad but manageable; panic dosing and a huge water change from a worried helper can harm the whole shoal.
Hand over the tank, not just the food
Write the brief as if the feeder has never seen your setup: which socket runs the light timer, where the food containers sit in order, and which evening the frozen treat replaces the pellet if that is part of your routine. A short trial visit while you watch is worth more than any written page, because you can watch them find the right container and check the outlet flow themselves. Everything on that written brief can live in KinsLe's Care Pass, which hands your feeder temporary clear access to the corydoras care routine and key tank details for exactly the days you are away.