Tape one laminated sheet beside the tank, not in a drawer. In a real problem — a heater stuck on, a filter gone silent at midnight — your sitter should not have to search the house or guess who handles fish. The sheet works because it gives a call order, this tank's normal numbers, and the few changes that mean act now rather than wait until morning.
The Call Order, Top to Bottom
List contacts in the sequence a sitter should use them. First, you: mobile number, where you are staying, and your return date. Second, a backup keeper — a named person, ideally within a short drive, who has agreed in advance to come out for a dead filter or a leaking seam, not just to feed. Third, an aquatic vet or a maintenance service that handles fish; many general vets do not, so confirm before you travel that this number takes fish emergencies. Fourth, the fish shop you actually buy from, which can often talk a sitter through a test result or hold a replacement heater for pickup.
Add one practical line under your own name: how much emergency spending you authorise without reaching you first. A sitter who knows they can buy a heater or bottled water conditioner immediately will act faster than one waiting for permission.
The Baseline Block
Under the contacts, write the tank as it normally runs. Record the usual temperature, the most recent ammonia, nitrite, nitrate and pH readings from the week before you leave, the date of the last water change and how much was changed, and exactly what feeding looks like — which food, how much, how often, and which days are skipped, if any. Note where the test kit, spare heater, buckets and water conditioner live.
That baseline is what turns a worried phone call into a useful one. A nitrate reading means little on its own; compared against last week's figure, a sitter and the shop can tell a genuine spike from this tank's normal level.
The Call-Now Triggers
Finish with three or four plain triggers written for a non-specialist: all fish gasping at the surface or hanging by the filter outflow, water suddenly cloudy with a sour smell, temperature several degrees above or below the normal figure on the sheet, or water on the floor or stand. Beside each, write the first move — usually call the backup keeper, then you — rather than instructions to start changing water or dosing anything. Untrained large water changes during a panic cause more losses than the original problem.
Note the equipment plainly too: which plug runs the filter, which runs the heater, and that the filter stays on at all times, including overnight.
Before You Leave
Walk the sitter through the sheet at the tank once, have them feed while you watch, and check the backup keeper still has a key or access. A sheet that has been talked through beats a longer one that has only been read. Keeping the identical routine, contacts and triggers in KinsLe's Care Pass gives your sitter the same instructions on their phone when the paper copy is across the room from the problem.