Aquarium Maintenance Tips

Consistent maintenance is how fishkeepers suceeed. A regular schedule keeps water parameters stable, catches problems early, and keeps fish healthy long term.

Water changes

A partial water change of 10–20% every two weeks is a good baseline for most tanks — more frequently if the tank is heavily stocked or if parameters are off.

Always treat new water before adding it to the tank. Tap water can contain chlorine, chloramine, and heavy metals that are harmful to fish and beneficial bacteria. Local tap water may also contain phosphates, iron, and other compounds that can affect water chemistry — contact your local water utility if you’re unsure what’s in your supply.

Testing

Test regularly to stay on top of what’s happening in your tank. The key parameters to monitor are:

• Ammonia — should always be 0 ppm
• Nitrite — should always be 0 ppm (except during the initial cycling period)
• Nitrate — keep below 20 ppm for most freshwater fish, below 10 ppm for saltwater, reef, and sensitive species
• pH — 6.8–7.4 for most freshwater fish, 8.1–8.3 for marine aquariums
• Carbonate hardness (KH) — a measure of your water’s buffering capacity, or its ability to resist pH swings. Low KH makes pH unstable and harder to manage
• Salinity — essential for saltwater and brackish tanks; see our Salinity article for target ranges

Recommended maintenance routine

Daily

• Observe fish behavior — changes in activity, appetite, or appearance can be the first sign of a water quality issue
• Check water temperature — sudden swings in either direction can stress or kill fish
• Remove any uneaten food — excess food breaks down quickly and can trigger ammonia spikes
• Check equipment to confirm everything is running properly
•  

Weekly

• Do a quick headcount of livestock. A dead fish can decompose rapidly and trigger a significant ammonia spike before you notice it
• Check for algae buildup on glass and surfaces
• Top off evaporation with treated fresh water (saltwater tanks only)

Biweekly

• Test ammonia, nitrite, nitrate, pH, carbonate hardness, and salinity (saltwater and brackish tanks)
• Perform a 10–20% water change
• Vacuum the substrate to remove accumulated waste
• Clean aquarium glass
• Rinse filter media in tank water — never tap water, which can kill beneficial bacteria
• Replace carbon and filter floss if present
• Inspect all equipment for proper operation

Monthly

• Do a deeper inspection of filter internals and replace any worn components
• Check and clean pump impellers and intakes
• Review livestock health and stocking levels — overcrowding is one of the most common causes of persistent water quality problems
• Compare current test results to previous months to catch slow shifts before they become problems

Conclusion 

Good maintenance isn’t about perfection, it’s about consistency. Stay on schedule, keep testing, and address small problems before they grow — and you’ll enjoy a healthy, thriving aquarium for years to come.