What the Card Has to Answer in Ten Seconds
An emergency card is read by someone who is already worried: the power has flickered, the tank sounds wrong, a fish is floating. That reader cannot absorb paragraphs, so the card is built from short lines in the order a frightened person asks questions. Is the water the right temperature? Is the filter running? Who do I call? Everything else on the card exists to support those three answers. Keep it to one card, large type, no abbreviations a non-fishkeeper would have to decode, and nothing that requires opening the cabinet and identifying equipment by touch in the dark.
Heater Settings, Written for Someone Who Has Never Kept Fish
Write the temperature the thermometer should show as one plain number, and next to it the heater's own setting — the number or dial position that holds it there — because in a panic people adjust the dial to match their worry instead of the thermometer. Add two orienting facts: where the thermometer lives ('stuck to the front glass, left side') and where the heater sits ('back corner, beside the filter'), plus the small pilot light that shows the heater is on. Then the crucial instruction: the heater is slow on purpose. Warming or cooling a tank takes hours, so the card should say to check, note the reading, and call you before turning anything — a heater cranked up in alarm can cook a tank that was only drifting slightly.
Filter Settings and What Working Looks Like
A sitter cannot judge a filter by its label, so describe what a working one does: a steady hum you can hear with the room quiet, water moving at the surface where it returns, and the intake tube clear. Write the filter's setting the way it appears on the unit — the flow position or dial state it should be left in — and state plainly that the filter stays on day and night; the plug it must never be switched off at is the one people most often mistake for the light's. Add where the filter's plug actually is, because 'the filter has stopped' is very often 'something got unplugged during cleaning, or by a pet brushing past the cabinet'.
The Do-Nothing List
Half the card's value is in what it forbids. Do not do a water change unless you have been told exactly how — treated water, matched temperature and a syphon are three skills a stranger does not have at midnight. Do not add any chemical, tonic or leftover treatment from the cupboard, however well meant. Do not feed extra 'to cheer the fish up', and do not move a sick-looking fish to a jug or bucket. Instead, the card gives the one safe sequence: look, note what you see and the thermometer reading, take a phone photo of the tank, and call. A photo sent to you settles most alarms in a single reply.
Where the Card Lives and Who Holds a Copy
Tape or magnet the card where the emergency will be noticed — on or beside the tank itself, not in a kitchen drawer among takeaway menus. Send a photo of the finished card to the sitter and to one backup person before you travel, so the information survives even if the card slips behind the cabinet. Review it whenever you change a heater or filter: an emergency card describing equipment you have since replaced is worse than none, because it sends a worried person hunting for a dial that no longer exists. Kept current that way, the card pairs naturally with KinsLe's Care Pass, which hands whoever is watching your home temporary access to your tank's key details — so the person facing the emergency is never working from memory.