The tank list: stability before you leave
Start indoors, several days ahead. Do the partial water change and any filter rinsing, in tank water as always, early enough that you can watch the aquarium run normally for a couple of days afterwards; a fault you cause the night before departure is the classic holiday disaster. Confirm the light timer by watching one full on-off cycle, test the automatic feeder over the tank while you are home if one is fitted, and check the heater against a thermometer rather than trusting its dial. Top the water level up to its mark so evaporation has room to work before the filter intake starts sucking air.
The pond list: pump, skimmer and net
Outdoors, the pump is the pond's heartbeat, so clear its intake cage, empty the skimmer basket, and confirm a strong flow over any waterfall or filter outlet. Stretch and peg the net properly: it keeps herons off the fish and stops wind-blown leaves sinking and rotting into an oxygen problem while nobody is watching. Top the pond up so the pump stays safely submerged even after a dry, windy week, and check that any floating plants are not smothering the whole surface. Trim back marginal plants that are collapsing into the water, since decaying vegetation is the pond's version of overfeeding.
Feeding: the pond plays by different rules
Pond fish live surrounded by food. Insects, larvae, algae and plant matter carry healthy pond fish through a week or more with no harm, and uneaten holiday blocks dissolving on the bottom do far more damage to water quality than hunger ever would. Skip pond feeding blocks entirely. Tank fish in a bare, filtered box have no such larder, so their plan is the one that matters: a tested feeder for longer trips, or a visitor with one measured portion and strict instructions that a second scoop is never kindness. Two systems, two feeding answers, and mixing them up helps neither.
One checker, one round, in the right order
Whoever visits should do the pond while it is light enough to see the fish and the water level, then the tank indoors. Give them the same style of alarm list for both: pump silent or waterfall dry outdoors; filter silent, water cloudy or fish gasping indoors. Ask for one photo of each on the first visit, pond surface and tank front, so you can compare against what normal looks like rather than reassuring yourself from memory. Agree that small things get reported the same day, because a pump heard struggling on Tuesday is a cheap fix and a pond found silent on Sunday may not be.
Both lists in one handover
The usual failure is not neglect but separation: pond notes on the fridge, tank instructions in a text thread, and a helper who only ever sees one of them. A KinsLe Care Pass keeps the pond round and the tank round as one handover with the property's pets, so the person walking your garden and your hallway carries both checklists, both alarm lists and your number in a single place.