Tank Maintenance – 10 Things That Need to be in Your Routine

Guppy Tank

Adding a beautiful freshwater aquarium to your home provides a number of benefits: stress relief, reduction in anxiety, and the joy of watching the results of your hard work. Whether you invest your savings into your tank or go the thrifty route, regular maintenance is required to keep your fish – and the tank – in peak condition.

Keeping track of changes and noting maintenance adjustments can feel daunting. Help yourself out by getting a notebook or planner: mark when filters need changing, record daily temperatures, and jot down amounts of food fed versus amounts leftover. Another option is the Aquarium Note app (or similar apps available via the Apple Store or Google Play): it keeps track of the fish, plants, and regular maintenance items for you.

Either way, breaking your regular tank maintenance down into the following 10 categories (arranged from daily tasks to monthly) will help keep your tank running smoothly.

Tank Maintenance #1: Fish

Daily monitoring of your fish should be a regular part of your routine, with careful attention to behavior, signs of infection, and symptoms of stress. Make a count of your fish (predation happens), and note any signs of stress:

  • Lack of activity 
  • Behavioral changes
  • Decreased appetite
  • Hiding
  • Fins clamped to the sides
  • Color change
  • Gasping for air at the surface

Resolving stress is tricky as you need to identify the trigger. Stress comes from a lot of possibilities including poor water quality, poor/improper diet, incorrect water temperature, aggressive tankmates, or too many tankmates. Poor water quality or an overstocked tank increases the likelihood of disease, and stressed fish are prone to infection.

Tank Maintenance #2: Food

One of the worst things you can do is overfeed your fish. The uneaten food degrades in the water, collects on the substrate, and clogs the filter. Setting up a reasonable feeding schedule for your fish is just as important as the cleaning schedule – as is monitoring the amounts of leftover food.

Never feed your fish more than they can eat in the space of about 3 minutes, and they only need to be fed twice a day – MAX! In fact a lot of aquarists recommend fasting fish once or twice a week. This replicates natural feeding habits. Just make sure you keep a record of which days you’re fasting.

Records will also help you determine if you’re overfeeding – an excess of leftovers is a good indication you need to cut back.

Tank Maintenance #3: Temperature

Whether you have goldfish in a cold water tank with a chiller or multiple species in a tropical tank with a heater, temperature maintenance is key in a freshwater aquarium. Fish tolerate some excursions out of their preferred temperature range, but constant fluctuations cause stress. Ensuring that your heater/chiller is functioning properly is monitored with your thermometer.


The easiest way to spot a problem is to check your tank’s temperature every day. Make a note each time you drop food into the tank and glance at the previous entry – you’ll notice trends before they become a problem. Include the time with each entry and note any possible outside influences:

  • Is the tank in direct sunlight?
  • Is the tank near an air conditioning/heating vent?
  • Did you remember to check the temperature of your replacement water during the water change?
  • Did you recently change the lights over the tank?

Tank Maintenance #4: Water

Water changes are a crucial part of tank maintenance: they remove/dilute harmful nitrogenous compounds, remove excess organic waste material, improve water clarity, and replace trace elements and essential minerals. Routine water changes of between 25-50% every week to two weeks (depending on the size and stock in your tank) help maintain a healthy balance.

When you first set up your aquarium and cycled it, you dropped the ammonia, nitrate, and nitrite levels to zero. While the addition of live plants and filters, particularly biological filters, continue to process these compounds out of the water, nothing removes them completely. Water changes are necessary to combat the excess build-up.

Water will naturally evaporate from the tank, but this doesn’t remove any of the accumulated toxins, so simply “topping off” the tank isn’t sufficient – those toxins will continue to build up and pose a health hazard to your fish.

Before you add any water into the aquarium, make sure it’s at the same temperature as the water in the tank – you don’t want to shock your fish! When performing a water change, it’s crucial to test not only the tank water, but the water you intend to use for replacement. Make sure your test kit has not expired before you use it, or you can end up with false readings. 

5-in-1 test kit

When testing the water, you’re looking for the following conditions:

KH (Carbohydrate Hardness)>4.5dH (80ppm)
*If any Nitrites are detected, test for Ammonia

If you notice values out of range, don’t panic – you can make some adjustments. For instance, there are a few ways to help balance pH in your tank if you see that value creeping up. KH is a measurement of pH stability within the tank; if it drops too low, the pH crashes. You can add 1/2 teaspoon of baking soda per 25 gallons of water to increase the KH by 1dH (17.8ppm).

Ideally, test the water in your tank every other week. Make sure you record your values so you track possible changes.

Tank Maintenance #5: Plants

Live plants provide a lot of benefits to freshwater aquariums: they assist with the nitrogen cycle, provide hiding places for the fish, add beauty to the tank, and provide a source of nutrition. They also require careful maintenance to keep them healthy. Unhealthy plants will die and decompose, dumping an extra burden into the tank environment.

Plants require CO2 in order to thrive – around 20-25mg/L. Monitoring the aquarium’s pH provides an idea of the CO2 levels, but the best measurement system is to obtain a glass drop checker. Drop checkers are filled with a colored indicator fluid: blue tells you the CO2 levels are too low, yellow too high, and green just right (get it? Green for plants?).

It takes a couple of hours for the indicator fluid to acclimate once it’s first introduced into the tank, and the fluid should be changed every month (it will turn transparent as it wears out).

Glass drop checker

Plants require a little TLC – tender loving care – to keep them in top condition. Regular trimming is an important part of your tank maintenance. Make sure you purchase aquascaping scissors – don’t just use any scissors you have lying around the house. All of those clippings then need to get skimmed from the tank so they don’t clog the surface and block the light.

Following water changes, your plants need regular fertilizing. The water change is a “reset” for them. While you’ve removed the excess chemicals and waste compounds, you need to reintroduce some growth material for the plants. Liquid fertilizers work best, though they require a little work on your part – about 5 minutes once a week.

This will ensure your plants continue to thrive, keeping your aquarium beautiful and that nitrogen cycling properly.

Seachem Flourish

Tank Maintenance #6: Substrate

You need to keep your substrate clean of debris (organic waste, uneaten food, and decomposing plant matter). If you have bottom-feeding fish, they help, but they aren’t the only solution – you’re going to have to do some of the work yourself.

Aquarium hydro-vacuum

A hydro-vacuum consists of a hose with an attachment that goes into the tank and sucks up the unwanted debris from the bottom. There are a variety available, some of which connect directly to your sink. Just consider your level of “vacuuming expertise” before you purchase one – siphoning into a bucket may be best so you don’t risk sucking tank residents into the sink!

To properly vacuum the substrate, follow these steps:

  1. Unplug all electronics. (You’re going to put your hand in the tank and water and electricity are a bad combination)
  2. Remove any plastic plants and other ornaments to clean separately, but leave at least a couple of places for your fish to hide.
  3. Set up your hydro-vacuum so that it has suction, and then push it down into the substrate. You should see gravel swirling in the attachment.
  4. You can crimp the hose to slow down the flow of water, if needed. Move the attachment along the bottom of the tank. Don’t let the gravel clog the hose.
  5. You may not get to the entire bottom before you empty 25-50% of the tank – just remember where you finished and start there the next time (this is where that notebook comes in handy – make a note of how far you get each cleaning).

Tank Maintenance #7: Algae

Nothing is more of a nuisance than algae on the walls of your freshwater aquarium. True, you can stock your tank with algae eaters to help stave off this irritation, but – just like with the substrate – you’re going to have to assume some responsibility. Algae develop from stagnant water, excessive light, and an abundance of nutrients, so if you aren’t performing your routine water changes, have an aquarium in direct sunlight, or are overfeeding your fish, prepare to wage war.

algae on tank wall

Regular cleaning is a MUST as soon as algae is spotted, and algae scrubbers are available to help. Attacking the pesky intruder during your water change, when the level in the tank is at its lowest, is your best option (prepare to invest some elbow grease). The addition of live plants to your tank will help as they compete for the same resources as the algae.

Tank Maintenance #8: Filters

All of the water in your tank flows through your filter at least five times an hour, and the media in the filter removes unwanted compounds that pose a risk to your plants and fish. You want to make sure the filter is running in top condition at all times, which means keeping up with regular media changes.

Each time you change out your filter media, make note of the date and type. Chemical filters, such as activated charcoal, are only good until their pores fill, and then they need to be replaced. Look at the manufacturer’s information and set a reminder for yourself so you stay ahead of things.

Mechanical filters trap debris and are usually foam blocks or sponges. Rather than being replaced, they require a rinse and removal of debris. Once they start to disintegrate, consider getting a new one.

Biological filters consist of pellets in a bag, and they nurture bacteria that break down waste. They require a rinse to remove physical debris and should only be replaced when they completely break down. Some filters contain all three media – check the manufacturer’s recommendation there.

Three-in-one filter

When you do your bi-weekly water change, service the filter. Clear out visible debris from the inside of the filter and wipe it out. Do NOT use any soap or cleansers! Remember, it’s attached to the tank, and anything you use on the filter will circulate through the entire aquarium.

For mechanical and biological filters, rinse them in the water you siphoned from the tank – don’t use tap water.

Tank Maintenance #9: Lighting

Lighting is important in freshwater aquarium maintenance. Your fish may be fine with the natural lighting of the room, but if you’re looking to breed, lighting is critical. If you have live plants in your tank, you need to provide a full 12 hours of overhead lighting each day in order to keep them healthy. Remember, those plants outcompete algae for resources, so it’s in your best interest to nourish them.

Aquarium lights need to be cleaned every two weeks. Even with covers and hoods, deposits build up, reducing the light entering your tank. Unplug the lights before you clean them and use an approved cleaner to prevent damaging the bulb or housing.

The bulbs should be replaced every year, even if they haven’t burned out.

Aquarium plants

Tank Maintenance #10: Electrical Equipment

As mentioned previously, electricity and water don’t mix, but there’s a lot of equipment your freshwater aquarium depends on in order to function. You want to build some time into your routine to make sure everything continues to work properly.

First things first, though, make sure you unplug everything to prevent a trip to the hospital!

Once a month, all of the cords need a thorough dusting.

Remove all of the tubes and hoses and inspect them for cracks, leaks, or blockages. Plastic degrades over time, and if you don’t pay close attention, you can miss a problem. They make hose brushes designed to clean such tubing, and this is the perfect time to employ them.

Air stones provide additional oxygen to your tank as well as creating water circulation. Replace the stones every month. If they become encrusted or dirty, they’ll increase the pressure on the pump and it’ll burn out faster.

Properly maintained aquarium


There’s a lot to remember in regards to maintaining a freshwater aquarium, but utilizing a management app or notebook/planner makes your job easier.

Setting up a regular schedule to handle fish counts and monitoring, proper feeding, temperature records, water changes, plant care, substrate vacuuming, algae problems, filter rinses, cleaning of the lights, and equipment maintenance will ensure that your aquarium remains healthy for years to come.

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