Aquarium maintenance schedule

A quick look each day catches most problems while they are still small. None of this takes more than a minute or two.

• Feed once, only as much as the fish clear in 2 to 3 minutes. Uneaten food is the most common cause of poor water quality, and many keepers fast their fish one day a week. See our feeding guide.
• Count your fish and watch them. Clamped fins, white spots, gasping at the surface, flicking against decor, hiding, or going off food are all early warning signs. See common fish diseases.
• Check the thermometer. A tropical community wants 24 to 26°C. A sudden change points to a failing heater (see water parameters).
• Glance at the equipment. Confirm the filter is still flowing and the heater's indicator light is behaving as it normally does.
• Remove anything fouling the water, such as obviously uneaten food, a dead leaf, or (rarely) a lost fish or shrimp.

The core of tank maintenance. Set aside half an hour, ideally on the same day each week so it becomes a habit.

• Test nitrate before you start, as a sanity check on how the week went (and ammonia and nitrite too if anything has looked off). The API Freshwater Master Test Kit is the standard. See water parameters.
• Change about 25% of the water for fresh, dechlorinated, temperature-matched water. This is the job that actually exports nitrate and replaces trace minerals. See our water changes guide, and the water conditioner calculator for the dechlorinator dose.
• Vacuum the open substrate as you drain, hovering over sand and planted areas rather than digging into them (see substrate).
• Wipe algae off the front glass with a scraper or pad before it has a chance to build up. See algae types and control.
• Check the filter intake for trapped leaves, snails, or a stuck fish, and clear it if the flow has dropped.
• Top up any evaporation with dechlorinated water. A top-up only replaces water lost to evaporation; it does not remove nitrate, so it is not a substitute for the water change.

Once a month, add a few jobs to the weekly routine. Best done on a water-change day, using the water you have just drained.

• Rinse the filter media in old tank water, never under the tap. Tap water's chlorine kills the bacteria your filter depends on. Just rinse the muck off the sponges; do not replace biological media. See how to choose a filter.
• Test pH, GH, and KH to catch slow drift. A falling KH is the usual reason pH starts to swing, so keep an eye on it. The hardness converter helps you read the numbers.
• Prune and tidy plants: trim fast growers, remove dying leaves, and replant healthy trimmings. See planted tank basics.
• Deal with stubborn algae: a magnet scraper for the glass, and clean affected decor in a bucket of tank water.
• Look over the equipment: check the heater is holding temperature against your thermometer, and that filter flow has not quietly dropped off.
• Wipe the lid and light, and check the lid for gaps. Many community fish jump, and a small gap is all they need.
• Restock supplies so you never run out mid-change: dechlorinator, test reagents, and a spare filter pad.

A short list of occasional jobs. Spacing them out, and never doing them on the same day as a big filter clean, keeps the tank stable.

• Replace mechanical media (filter floss or pads) once it is too clogged to rinse clean. Stagger media changes so you never swap everything at once and lose your bacteria. See aquarium filters.
• Deep-clean the filter: impeller, intake tube, and housing, all in tank water. A drop in flow is usually a dirty impeller or a blocked tube.
• Check expiry dates on your test-kit reagents and dechlorinator. Old reagents drift and give false readings.
• Verify the heater against a separate thermometer and inspect its cord and seal. Replace any heater that can no longer hold a steady temperature.
• Clean or replace airstones (they clog over time), and check any non-return valve on an air line.
• Inspect the seams and stand: look over the silicone for any weeping, and confirm the tank is still sitting level.