Guide
Aquarium maintenance schedule for beginners
A simple weekly and monthly routine so your tank stays healthy without feeling overwhelming.
- Weekly: 20-30% water change with a gravel siphon, test ammonia/nitrite/nitrate/pH, and do a quick visual check of fish and equipment.
- Every two weeks: wipe the front glass, trim dead or overgrown plant matter.
- Monthly: rinse filter media in old tank water (never tap), inspect heater, filter, and lights for wear.
- Temperature match your top-up water to within 1-2°C (2-3°F) of the tank - cold water shocks fish more than most beginners realise.
- Never clean the filter and do a water change on the same day - you'll crash your beneficial bacteria and your water quality at once.
- Pick a fixed day and stick to it. Consistency matters more than perfection on any individual task.
Why consistency beats intensity
Most aquarium problems - ammonia spikes, algae outbreaks, fish disease - don't arrive without warning. They build slowly over missed water changes and skipped tests until the tank tips into a crisis. A steady, boring routine is the single biggest thing separating hobbyists who rarely have emergencies from those who spend weekends doing frantic deep cleans.
The goal of a maintenance schedule isn't to make your tank look perfect every week. It's to keep parameters stable, remove waste before it oxidises, and catch problems early when they're still easy to fix. Small, regular interventions are far less stressful for your fish - and for you - than infrequent overhauls.
Weekly tasks
Water change
Aim for 20-30% of tank volume once a week. The old guidance of "10-15% is enough" gets repeated constantly and it's often too conservative, especially in stocked tanks. Nitrate accumulates faster than most beginners expect, and small water changes don't dilute it adequately.
Use a gravel siphon, not a jug. Draw the siphon slowly across the substrate in overlapping passes - you're vacuuming out fish waste and uneaten food that's rotting between the gravel. In planted tanks with fine substrate, hover just above the surface rather than plunging in and disturbing roots.
Refill with dechlorinated water matched to your tank temperature. A difference of more than 2°C (3-4°F) can send fish into temperature shock, which suppresses their immune system and opens the door to ich and other opportunistic infections. Mix your top-up water in a clean bucket and add a dechlorinator (sodium thiosulphate-based products like Seachem Prime work well) before it goes in the tank, not after.
Tap water temperature in winter can drop significantly. Always check with a thermometer before refilling - cold tap water that feels "about right" to your hand might be 5-6°C colder than your tank.
Test key parameters
Test ammonia, nitrite, nitrate, and pH every week, especially in the first six months. In a fully cycled tank, ammonia and nitrite should read zero. If either shows any reading above zero, something is wrong - overfeeding, a dead fish, filter damage, or a stocking problem.
Nitrate is where most people get complacent. Below 20 ppm is ideal for most community fish; above 40 ppm for extended periods stresses fish and accelerates algae growth. Your water change schedule exists largely to keep nitrate in check, so if it's creeping high week-on-week, you either need larger or more frequent changes, or your tank is overstocked. See our guide on aquarium water parameters for target ranges by fish type.
Log every result. It sounds tedious until the day you notice nitrate has been climbing for three weeks and catch a filter problem before it becomes a fish loss. App-aquatic lets you log test results from a phone and flags anything outside normal range automatically.
Testing only when something looks wrong. By the time your fish are gasping or your water is cloudy, the problem has been developing for days or weeks. Weekly testing during normal conditions gives you the baseline to recognise when numbers shift.
Visual check
Spend two minutes watching your fish before and after feeding. You're looking for: fish hiding that normally don't, clamped fins, white spots, frayed edges, laboured breathing, or any fish that isn't eating. Check that your filter is pushing water visibly, your heater light is cycling normally, and nothing smells off when you lift the lid.
This takes almost no time, but it's how you catch ich at three spots instead of thirty, or notice a heater stuck on before it cooks the tank.
Every two weeks
Glass cleaning
Algae on the front glass is normal and doesn't mean your tank is dirty. Green spot algae appears on glass that gets reasonable light - it's harmless but obscures your view. Use an aquarium-safe magnetic scraper or a dedicated algae pad. Don't use kitchen sponges or anything that's touched soap.
For stubborn green spot algae (the hard, circular patches), a razor blade scraper on glass tanks works well. Never use one on acrylic - it scratches immediately and permanently.
Side and back glass can be left - algae there provides grazing ground for fish like otocinclus and nerite snails, and poses no problem.
Plant trimming
If you have live plants, remove yellow or brown leaves and cut back stems that are shading lower plants or reaching the surface. Decaying plant matter releases ammonia as it breaks down - not catastrophic, but adding a slow background source of ammonia to a tank you're trying to keep stable is pointless. Trim before your water change so you can siphon up the trimmings.
Monthly tasks
Filter maintenance
This is the task most beginners either skip entirely or do wrong. Your filter media is colonised by the beneficial bacteria that process ammonia and nitrite - the same bacteria your tank spent weeks building during the nitrogen cycle. Killing them off accidentally is one of the fastest ways to crash a healthy tank.
The rule is simple: rinse filter media in water you've just removed from the tank during a water change. That water is dechlorinated and at the right temperature. Tap water - even briefly - is chlorinated and will kill a significant portion of your bacterial colony. Squeeze sponges gently, rinse ceramic rings, and put everything back. You're removing trapped debris, not sterilising anything.
Don't replace all your media at once. If you run two sponges, replace one at a time, six weeks apart. If you run a cartridge-based HOB filter, resist the manufacturer's advice to replace the cartridge monthly - that cartridge is your bacterial colony. Replace it only when it's physically falling apart, and keep your old one running in the tank for two to three weeks alongside the new one to seed it.
Filter cartridge replacement instructions are written to sell filter cartridges, not to protect your fish. Most sponge and ceramic media lasts years with proper rinsing. You don't need to replace it on a monthly schedule.
Equipment check
Once a month, look carefully at your heater, filter intake and output, airline tubing, and light fittings. Heaters can fail in two ways: they stop heating (fish get cold slowly) or they stick on (tank overheats rapidly). The stick-on failure is the dangerous one. A separate thermometer - not the heater's built-in dial - is worth having so you notice a temperature anomaly before your fish do.
Check filter impellers for debris. A partially blocked impeller reduces flow without stopping it, so the filter appears to work while actually turning over far less water than it should. A quick pull of the impeller cover and a rinse sorts this in two minutes.
Keep a spare heater if your collection grows to more than one tank. A heater failure overnight in winter can kill a tropical tank. A spare costs less than restocking.
What most maintenance guides miss
Don't do everything on the same day
Spreading major tasks across a week reduces the load on your biological filtration at any one point. If you clean the filter on Sunday, do your water change on Wednesday. Never clean the filter and do a large water change simultaneously - you're removing bacteria from the media and from the water column at the same time, and you'll almost always see a temporary ammonia spike.
Overfeeding is a maintenance problem
Most beginner tanks have too much waste not because of stocking but because of feeding. Uneaten food left on the substrate drives ammonia, feeds nuisance algae, and clouds water. Feed only what fish consume in two to three minutes, once or twice a day. If you're doing everything right maintenance-wise but your nitrate keeps climbing, reduce feeding before you increase water change frequency.
New tanks need more attention
In the first two to three months after cycling, test twice a week and change water weekly without fail. Your bacterial colony is still establishing and any disruption - a new fish, a cleaning product near the tank, a temperature swing - can send parameters unstable. After six months of stable readings, you can be more relaxed about the odd missed week. Not before.
In most cases, a consistent test-and-change routine would have flagged the problem days before fish showed symptoms.
How often to change water - the actual answer
The hobby debates this endlessly. Weekly 20-30% changes suit most community tanks stocked at moderate density. Lightly stocked, heavily planted tanks can sometimes get away with less. Heavily stocked or predator tanks may need two changes a week. The only way to know what your tank needs is to test nitrate before a water change - if it's above 20 ppm, you're not changing enough water, often enough. Our guide on how often to do water changes goes into this in more detail.
Building the habit
Pick one fixed day for your main water change and test - Sunday afternoons work well for a lot of people because there's no time pressure. Put it in your calendar with a reminder. Do the visual check every time you feed. Everything else slots around that anchor.
The biggest threat to a maintenance schedule isn't laziness - it's life getting busy and "I'll do it next week" becoming three weeks. Having a logged history of your parameters makes it much easier to see when things are drifting and act before there's a problem. That's exactly what a test log is for, whether it's a notebook or an app.
If you're still figuring out which fish to keep, our best fish for beginners guide and free stocking calculator are good starting points - the right stocking level makes every maintenance task easier.
Track your parameters and get care reminders with App-aquatic.
Get the free appCan I skip a week of water changes if the tank looks fine?
Occasionally, yes - a healthy, lightly stocked tank won't crash over one missed week. But "looks fine" doesn't tell you what your nitrate is doing. Test before you skip, and if nitrate is already at 20 ppm or above, do the change anyway. Making skipping a habit is where problems start.
How do I know if I'm changing too much water at once?
Fish that scatter or show stress behaviour immediately after a water change usually means the top-up water was too cold, too warm, or not dechlorinated properly - not that you changed too much. Large water changes (up to 50%) are safe if the replacement water is matched in temperature and treated. The volume isn't the risk; the quality of the replacement water is.
My filter has been running for six months - should I replace the media?
No, not unless it's physically disintegrating. Sponge and ceramic media that's rinsed monthly in old tank water works indefinitely. Replacing it on a schedule kills the bacterial colony you've spent months building and can cause an ammonia spike. Only replace media when it's structurally failing.
Do I need to test every week once my tank is established?
In the first three to six months, yes, every week without exception. After that, once a week is still good practice, but experienced keepers with mature, stable tanks sometimes drop to every two weeks. If you add new fish, change your feeding routine, or notice any behaviour change, go back to weekly testing immediately.
What's the minimum maintenance I can get away with?
Realistically: a 20% water change and parameter test every week, glass wipe every two weeks, filter rinse once a month. That's probably three to four hours of actual work per month for a standard community tank. Going below that, you're gambling on your stocking level and feeding habits being light enough to compensate - and most beginners' tanks aren't.
More guides · How often to change water · Water parameters · App features