Start the Briefing at the Bottom of the Tank
A corydoras catfish spends its life on the substrate, sifting with its whisker-like barbels and resting in a loose group, so brief your sitter to watch the tank floor before anything else. Walk them past the glass and point out where your corys normally settle, how many there are, and how they shuffle forward in short bursts between rests.
The Surface-Gasping Rule for a Corydoras
Repeated trips to gulp air are the clearest emergency sign in a corydoras, and your sitter should treat them as a call-you-now event. Corys do take an occasional breath at the surface, so explain the difference between one unhurried rise and constant, frantic up-and-down swimming with rapid gill movement. If they see the frantic version, their first checks are simple and safe: is the filter running and rippling the surface, is any air stone still bubbling, and has the lid or a fallen decoration blocked flow. They should never tap the glass, chase a fish with a net, or lift a cory out to look at it, since handling damages delicate fins and barbels and adds stress to an animal that may already be short of oxygen.
Power, Heat, and the Corydoras Tank
A power cut matters quickly for a corydoras because still, warming water holds less oxygen at exactly the level where these fish live. Show your sitter where a battery-powered air pump is kept if you own one, how to drop its air stone in, and which plugs belong to the filter and heater so nothing is unplugged by mistake during a reset. If the tank has gone cold or hot while they were out, the instruction is to restore power, leave the lid closed, and phone you for the next step instead of pouring in water of a different temperature to fix it fast.
A Safe Water Change, Corydoras Style
If you pre-approve one intervention, make it a small partial water change done exactly your way, because a corydoras sits in the waste layer that collects at the bottom. Leave a bucket, your siphon, and your water conditioner together with a note on how much water to remove, how to refill slowly with matched, conditioned water, and why the refill should trickle in rather than dump and stir the substrate into a cloud. Tell the sitter never to scrub the filter media, replace a cartridge, or deep-clean the gravel during your trip, since that cleaning can crash the bacteria the tank depends on while the fish are already coping with change.
Feeding and the Quiet Signs
Overfeeding is the slow emergency your sitter can prevent, so portion a corydoras group's sinking food in advance and show them how little actually reaches the floor. Ask for a daily glance at each fish: barbels worn short, a reddened belly, white patches, or one individual that stops joining the group's evening shuffle all deserve a photo sent to you the same day, not a wait-and-see note at the end of the trip. A sitter should also know not to add any treatment, salt, or extra product to the water on someone else's advice; your number and your aquatic shop or vet contact are the only authorities they act on.
Leave the Corydoras Handover in Writing
Finish the briefing standing at the tank, with your sitter repeating the gasping rule, the power checks, and the one approved water change back to you. Keeping that sheet inside KinsLe as a Care Pass means the person watching your corydoras can pull up the group count, the safe checks, and your contact order on their phone the moment the group starts swimming at the surface.