How to Clean a Fish Tank

syphoning aquarium

This article will explain how to clean a fish tank in a professional way

syphoning aquarium

What you are trying to achieve

You need to have 2 goals when cleaning a tank. The first is to clean up the appearance of the glass in and out, the gravel, ornaments, equipment and plants, and the other is to clean up organic pollutants in the water which might not be visible to the eye. The first is for your viewing benefit while the second is for the fish’s benefit in terms of health.

Equipment and Supplies needed

You will need :

  • Matured and dechlorinated water (20 litres. More for a bigger tank. Less for a smaller tank.) and warmed to the temperature of your aquarium
  • An algae pad for cleaning the inside glass of the aquarium.
  • A large bucket 20 litre bucket.
  • A siphon gravel vacuum with tubing
  • New filter media may be needed
  • An old credit card/store card or other similar piece of plastic to scrape off stubborn stains.
  • White vinegar
  • Old but clean towel
  • Old but clean cloth

Step by step cleaning your fish tank

Remember your fish do not like being disturbed. This method of cleaning your glass involves only a partial water change. Also you should not remove your fish while you are cleaning the aquarium. That is the best way to reduce fish stress.

Get your replacement water ready. If your tank is new you will need to prepare 20% of the volume of your aquarium in new water. To prepare the water, leave the water in a bucket for 24 hours or use a dechlorinator chemical. The use some boiled water to bring up the temperature of your replacement water to that of your aquarium.

Turn off all electrical equipment. Once you have turned off all equipment then you will have to do all your cleaning tasks without pausing because the water will start to cool and the biological bacteria in your filter will start dying after an hour of the filter being switched off. Note: do not remove your heater from the water for cleaning for at least 15 minutes because it will overheat out of the water.

Use your algae cleaner and scrub the inside of the glass to remove algae or other internal growths. Clean the front and sides, but leave the back glass. The algae is actually healthy for the fish because of its cleaning properties and the biological action of bacteria within the algae. Some fish even feed off the algae.

Take out any ornaments, rocks and equipment that have become coated with algae. Clean these objects with the algae scrubber and then replace them back in the aquarium. Remember to put all these objects back in the exact place from where they were removed, this will reduce stress to the fish in your aquarium.
Wipe down plant leaves with your algae scrubber but do not remove them from the aquarium. Plants do not like to be disturbed and might die back if you interfere with their roots.

If your filter has slowed down then you will need to take out the aquarium sponge. If you have other filter medium that has become clogged then you should change about 50% of this medium and replace with new filter medium. With a clogged sponge, you need to take the sponge to a sink and give it a good squeeze until most of the mulm comes out. Do not clean with tap water or cold water because this will kill off the essential bacteria that biologically filters the water. If the sponge has become too clogged then you will need to cut the old sponge in half and cut the new sponge in half and put the old and new sponge back into your filter.

After cleaning your filter the water may be cloudy for a while. Do not worry this cloudiness will be filtered back into the filter and some of it will drop to the aquarium floor where you can syphon it off later.
With your old credit card start scraping the inside of the aquarium above the water line. Use some water to soften the residue. Then use the sharp edge of your credit card at an angle and push firmly to scrape the glass clean. Take care not to scrape the silicone, because you may cause a leak.

Make a mark with a felt tip pen at about 20% of the way down the aquarium to use as a guide to how much water to syphon out.

Syphon through the gravel use the base of the vacuum tube to disturb the gravel or sand to release trapped pieces of dirt. Syphon out any loose algae that has been produced by your scraping the aquarium.
Your syphoning should result in about 20 litres of water being removed.

There will be some gravel or sand syphoned out with your water but don’t worry, it sinks to the bottom of the bucket.
Pour the dirty water away but take care not to pour out your gravel/sand. Then just rinse out the sand/gravel under running water until it runs clean. Then carefully pour away all the water. Replace the cleaned gravel in the aquarium.
Pour the newly mixed water into the aquarium. Turn back all the equipment.

Now you can start to clean the outside of the aquarium. Use white vinegar, which you may need to dilute depending on the concentration. Dip an old but clean cloth into the vinegar and use the cloth to wipe the outside glass. Clean it in the same manner as you would clean your windows. Do not use any soaps, detergents or any other cleaning agents, because these are usually lethal to the fish.

Once you have cleaned all your aquarium with the white vinegar you will need to rinse off any residue. You do this by rinsing out your cloth in warm water. Wipe each surface of your aquarium with the wet cloth and then dry down with the dry towel. Your aquarium should truly sparkle. Finish off the front before moving to each side in turn.

If the hood is dirty, you can also clean the hood in the same way as you cleaned the glass, but be careful that no vinegar falls into the water because it might harm the fish.

If there is still dirt at the bottom of your aquarium after this procedure then wait a few hours then syphon off this dirt and then prepare some water to replace this water. Replace the next day when the newly prepared water has matured. Make sure this water is at the same temperature as your aquarium.

Cleaning is now complete. You should have given your aquarium a new lease of life with this makeover. The preferable fish is otocinclus. Use several in the aquarium. Use more for larger aquariums.

Cleaning the tank: preventative measures

If you are getting too much algae growing or your aquarium water is becoming pea-green then you need to remove the cause. Algae feed of nitrate in the water and use excess of light, especially daylight.

To reduce the light you should first of all remove all sources of direct sunlight into the aquarium. If that is not the cause then you will need to reduce the duration of time your aquarium lights are on and perhaps reduce the strength of the bulbs. You could also try increasing the number of plants in your aquarium. The plants should eat up the nitrate before the algae in order to starve the algae.

To reduce the nitrate, feed the fish less and syphon daily any waste matter such as uneaten food, food poop and dead leaves on the aquarium floor. Also you could increase the frequency of your aquarium’s water changes. Remember to replace with dechlorinated water at the same temperature as your aquarium.

Another way to help reduce algae in the aquarium is to have fish that eat algae. These fish will continually browse on the algae thereby reducing your need to clean the algae.

And finally have two filters instead of one to double the amount of filtration in your aquarium and so improve the speed of waste removal in the aquarium.

Water: the essential element for fish

The texture of good quality water is subtle

Water: the essential element for fish

The texture of good quality water is subtle
The texture of good quality water is subtle

On a very basic level water is 99.98% H2O in a liquid that your fish swim, eat, breathe and excrete into. What about the other .02%? Is it important? Of course it is. It is these minute quantities of dissolved gases and dissolved solids that makes all the difference in whether the water is hospitable or poisonous to the fish. It is this 0.02% of dissolved substances that make sea water, river water and lake water different from each other. Note that seawater has a much higher level of dissolved salts of around 3.5%. It only takes minute quantities of the common gases such as ammonia, carbon dioxide or insufficient oxygen to poison or drown fish. Likewise it only takes a small amount of pollution or the wrong type of chemical to be dissolved in the water to poison and kill fish. But when conditions are just right or within reason then your fish will thrive without much care from you.

Creating a generic biotope for your fish to live in

The most common elements of an aquarium biotope
The most common elements of a biotope

As a fish keeper is is your responsibility to recreate a reasonable biotope for your fish that is as close as possible to the fish’s natural environment as you can.

Water has dissolved gases such as oxygen, carbon dioxide, nitrogen, ammonia and chlorine. Some of these gases are poisonous while others are necessary for fish to breathe. Water also contains dissolved minerals that determine the general hardness of your water. Some fish thrive in very hard water with a high ph, while other fish prefer much softer water with a lower ph. Organic matter can also dissolve in the water, usually darkening the water and acidifying it.

A biotope should include a substrate, plants and a source of light with the temperature of the water kept within a suitable range for the plants and fish. The choice of subrate includes gravel, sand, and even soil. Soil is usually topped with gravel. Other less essential features you might want to include in your fish’s biotope could include rocks, roots and branches.

The Lake Malawi Biotope explained here

The Amazon Biotope explained here

Is tap water safe for fish?

Is tap water safe for fish
Is tap water safe for fish

Tap water direct from the tap is not suitable for use in an aquarium. The main problem is chorine which water companies put in the water to kill off any potential bacteria in the water. To remedy this you need to leave your tap water standing in a container for at least 24 hours. This allows the chlorine to evaporate. This can be achieved by using buckets of water or water barrels to store the water.

Another danger to your fish is from dissolved copper which can come from copper pipes. Water that comes into contact with copper will slowly absorb the copper. This problem is worse for new copper pipes. But this can be remedied by running your tap water for a few minutes until uncontaminated water starts to come through. Copper is poisonous and even copper coins left in your aquarium will slowly dissolve and kill your fish.

If you are going to be serious about the quality of your fish’s water then you should buy a water test kit. A good test kit will test ph, ammonia, nitrite and nitrate as well as general hardness.

If you are a new fish keeper who wants the best chance of keeping your fish healthy and alive then test your tap water before you buy any fish. When you know the ph and hardness of your water then you can buy fish that prefer the water from your tap. Adjusting your water to suit fish that like a different type of water is best left to the advanced aquarist who don’t mind the extra effort. Some fish when kept in the wrong type of water will simply die after a few weeks and certainly won’t thrive.

If you are a more experienced aquarist then you can start adjusting the ph and hardness of your tap water so that you can keep the more delicate species of fish. To soften your water you can buy a reverse osmosis device that will remove the minerals from your water. Such water is usually too soft and must be mixed with unfiltered tap water to achieve the correct level of hardness. You can also use rainwater collected from a safe source.

To adjust the ph of your water you can either use a muslin bag containing peat moss to acidify your water or you can use calcium carbonate sand to alkalinify it instead. In order to reach the correct ph level.

All these procedures are complicated and time consuming and even prone to error. Messing with your tap water usually means you will have to monitor changes in your water conditions to maintain it. To make this complicated process a little easier it is best to prepare large batches of water in say a 200 litre barrel all in one go and then draw off water as needed.

I recommend that you don’t bother with all this messing around and just buy fish that can do well in the water that comes from your tap. There is usually quite a variety of fish that will suit your water conditions but you may have to avoid a particular species of fish that you might be keen on.

What water conditions are best for fish?

Normally the ph used in most freshwater aquaria ranges between 6.0ph and 8.3 ph. However Lake Tanganyika fish like an even higher ph, even as high as 9.0ph. And they also like hard water. Ph nearly always varies together with hardness. High ph above 8.0 usually means very hard water, while low ph of 6.4 or less coincides with soft water. Some amazonian fish like water that is of a ph less than 6ph and have very soft water.

Most of the commonly available fish in your aquarium prefer an average ph around 7ph and a medium level of water hardness. Not only that but such species can also tolerate a wider variation away from this medium than other more exotic species. Tank bred fish that have been bred in aquaria for several generations are overall more adaptable to variations in aquarium conditions compared to their wild caught counterparts.

Most average species will live in a wide range of possible water condititions. However, when it comes to breeding the ph and hardness must more closely resemble the fish’s conditions in the wild. Only then will some fish be capable of breeding and their eggs hatching.
Water hardness

This is a measure of the amount of dissolved minerals in your fish’s water. The most common minerals are calcium, magnesium and sodium.

These dissolved minerals are also essential for the health of your fish and plants.
Most cyprinids, tetras, rasboras and similar river fish like soft water. Most livebearers, Malawi fish and Tangayikan fish prefer quite hard water.

Plants also show a similar type of preference for different levels of hardness depending on the plant species.

Iron for fish health

Plants require minute levels of dissolved iron for optimum health as do fish. Fish acquite iron from their diet while plants will absorb it directly from the water. Pure iron quickly rusts in water making it unusable for the plants and animals. Feeding fish iron rich fish food will not only provide iron for the fish but allow the fish to provide manure that is rich in iron for the plants use.

Dissolved oxygen in water that fish breathe

Dissolved oxygen is essential for fish to breathe. The main source of oxygen in an aquarium is through the surface of the water. So a large surface area of water is essential to allow sufficient oxygen to dissolve into the water to replace the amount of oxygen that the fish breathe in through their gills. Also excess carbon dioxide that the fish release into the water from their gills has to be released from the water through the surface of the water. Plants also give off oxygen when they are in bright light, but will release a small quantity of carbon dioxide at night.

It is best not to rely on the quantity of oxygen that plants produce during the day to supplement the amount from the surface because this source of oxygen stops at night. If you see your fish gasping for air very early morning this is a sign that there is not enough oxygen and too much carbon dioxide in the water in the night so you will have to reduce the number of fish in the aquarium. This can also be a sign you have too many plants.

Fish waste in water

One lethal cause of fish deaths is ammonia poisoning which burns the skin and gills of the fish while also displacing oxygen in the water. Ammonia comes from fish waste and from decaying fish food and other decaying organic matter. In a new aquarium there will be no ammonia but this will build up over the fish few weeks. If you are new to fish keeping you will see your fish as being fine for the first week and may not realised that the fish are slowly but surely poisoning themselves in their own waste matter.

To overcome this you need some way to remove the ammonia as it gets created. You will have to for the first 6 weeks have to do daily water changes, use a filter and make sure that you under stock your tank until it is mature. Also avoid any uneaten fish food being left in the tank that will quickly rot and cause an ammonia spike.

A filter is not just for removing particles from the water but also for providing a base for the growth of bacteria that digest ammonia converting it into nitrite which is also poisonous. Later on another set of bacteria develops that will digest the nitrite converting it into nitrate which is much less harmful. This process takes between 4-6 weeks from new. So partial water changes are needed daily until the filter matures.

This is better explained in cycling your aquarium

Plants take up nitrate but usually not enough so you will need to keep doing partial water changes, perhaps once a week. 10% of the water changed is a reasonable amount of water change.

During this filter maturation period you should test your water daily with a test kit and if the ammonia or nitrite reading becomes particularly high then you will have to do another partial water change to bring it down to acceptable levels.