The aquarium owner’s Sunday maintenance list

At 9:12 on Sunday morning, the tank is doing its best impression of a small, self-sufficient world. Then you notice the water line is low, a plant has floated loose, and you cannot remember when the filter was last rinsed.

The job is deciding what not to do

Aquarium care is full of actions that sound sensible in isolation: clean the glass, change some water, trim the plants, rinse the filter, check the temperature, and test the water.

The difficulty is that these jobs do not all belong in every week. A useful plan depends on the tank, its inhabitants, equipment, and recent maintenance.

Set up a Routine for a 60-litre tropical freshwater tank with six small fish, two snails, live plants, a sponge filter, no CO₂ system, a usual water-change amount, a normal temperature range, and clear boundaries around jobs that require checking first.

Its memory can hold the last five Deliveries and a compacted summary of older ones, so recent maintenance does not disappear from the plan.

A Delivery that tells you what to do next

Plain markdown is enough. The Delivery should make its assumptions visible, separate observation from intervention, and say what to leave alone.

It can lead with the one job that belongs on this week’s list, then ask for the few observations that will improve the next run.

If you report that the water change was completed, the plant was replanted, or the filter is clogging sooner than usual, the next Delivery has something concrete to work with.

It changes the moment before the chore

The aquarium still needs a person. That person just no longer has to reconstruct the whole maintenance history while holding a bucket.

A standing Routine keeps returning to your tank: its size, equipment, recent jobs, and the details you report. It can tell you what to check, what to do, and what not to disturb out of habit.

Read the output beside the aquarium, do the parts that apply, and leave feedback for the next run.

Why the weekly cadence matters

Set the Routine for Sunday at 8am, or for the evening before the day you usually maintain the tank. Pause it when you are away, run it on demand after a major change, or duplicate it for a second tank with different needs.

The standing instruction should lead with what changed, separate checks from actions, state what should be left alone, never invent a measurement, and keep medication, disease diagnosis, and emergency advice outside the routine checklist.

A good aquarium plan is not one that fills the page. It is one that prevents unnecessary fiddling.

```markdown
# Aquarium check · Sunday 9 August 2026

## This week’s plan

1. Check temperature and fish behaviour before feeding.
2. Remove the loose plant stem and replant it.
3. Change 12 litres of water.
4. Leave the sponge filter alone this week; it was rinsed on 26 July.

## Record for next Sunday

- Temperature:
- Any unusual behaviour:
- Plant condition:
- Water clarity:
```