Cleaning the aquarium FAQ

Why do people decide to clean their aquariums?

Generally, there are three basic reasons to clean the fish tank. Firstly, the tank smells. The reason for the smell varies depending on the fish; excrement fails to be filtered, pieces of old food gather on the bottom resulting in dead fish somewhere in the tank. It is important to install a strong enough filtration system in order to keep good conditions in the tank. Still water naturally smells and there are even aquariums without filters which contain many plants, which bring stable chemistry.

The next reason to clean the aquarium is that it is overgrown with algae.

You should bear in mind that algae usually grow in tanks where there are not enough plants, nitrification bacteria, or there is very bright lighting. In this case, you should buy some algae eater, pleco fish, cory fish, etc. The algae is a natural part of aquariums and it helps to keep good water conditions and chemistry. Fish excrement falls to the bottom of the tank and it becomes the part of substrate. If the substrate is of good quality, it eliminates harmful wastes and changes them into nitrates which mostly consist of oxygen. If the aquarium contains enough aquatic plants, algae will not grow because all the fish wastes will be eliminated by these plants and nothing remains for algae. On the other hand, if you have bright light in the tank, many plants will not stop growing algae, because light naturally supports growing all the plants, even algae.

The third most common reason of cleaning tanks is that the water becomes brown/yellow.

Such colours are caused by driftwood, roots and other decorations. There is no need to clean the water, because it is natural and many biotopes in the world do not have crystal clear water. For example, South American rivers and creeks flow through rainforests. A natural part of these waters are trees and which keep them a brown, yellow or black colour. Even driftwood causes dark water colours, it is welcome by pleco fish and cory species. I recommend you place some roots or driftwood into the tank, because it means new places here fish can hide. Some species are active through the night and they don’t like light. Ancistrus species need shelter for their happy life, breeding and for playing around. All plastic decorations may be nice, but they won’t replace the need for a more natural environment in the tank.

People usually clean their tanks every 2-4 weeks. I don’t clean my tanks and only add the amount of water which has evaporated. I decided for this strategy years ago, because my fish were stressed during the cleaning process. Fish are stressed because of cutting plants and cleaning the filter. Imagine yourself and your family as fish and imagine your house as an aquarium. What would happened if any "higher power" came to your home once per two weeks without your asking. What’s more, you would not know why and when. I think you would get dizzy about it (however, I wouldn’t object if someone cleans up my house).

Nitrification bacteria exist for of a reason and they’re needed in all aquariums.

You shouldn’t kill these organisms as they help to maintain water clarity by consuming waste. It usually takes 2 months until they are able to efficiently filter the water. In cooperation with a good filter, they guarantee stable conditions without disease. All my fish are healthy and they’re not dying. However, you could help this process in the first two-three months of running the new tank by changing 10% of water each 2 weeks.

By the way, when we’re talking about setting-up a new aquariums, we should focus on the importance of using clean decorations, tank parts and the tank itself. Everything what you put into the fish tank should be clean of bacterial organisms and any potentially harmful objects like sharp shells and so on. Because of this you have to boil all the new objects before introducing them. Don’t forget to completely clean the whole tank if you suspect there is any disease. You will avoid losing all fish and plants.

As you can see, there’s really no reason to clean the tanks on a regular basis. Unlike cichlid aquariums, community tropical aquariums don’t need to be cleaned much. Since cichlid tanks don’t contain many plants at all, nitrification bacteria need more time to establish a large colony. This is why you need to change 10%-20% of water on a regular basis each 2 weeks. In nature, there are lakes without plants or filtration and even they allow fish to live. So generally, every tank could exist without cleaning, which might be more harmful than helpful in some cases. Of course, small aquariums need to be cleaned because their ecosystems aren’t as stable as ecosystems in larger tanks. In my opinion, larger tank means less problems.