Plants are just filtered dirt

Everyone starts once. Unlike other hobbies, the world of aquaristics is not necessarily self-explanatory and only forgives initial mistakes to a small extent. That is why it is really important to do your research beforehand. Of course, it is normal that everything does not work out at the beginning and that a watchful eye and great interest ensure that the residents are still okay.

We have compiled the typical beginner mistakes from our experience in customer service and the many letters and questions. The experienced aquarist may smile, but let's be honest, you surely made one of the mistakes when you started out, right?

The timer

A simple timer can make an aquarist's life a lot easier. Lighting times, CO2 addition and metering pumps can be controlled here. It is often forgotten that a filter does not do the job of a vacuum cleaner and is only supposed to suck in "dirt" from time to time, but that this is where the heart of the aquarium lies and the biological degradation processes are largely taken care of. For this work, the bacteria must be continuously supplied with oxygen and “work”. A filter should therefore never be switched off for more than a few minutes, as the bacteria die and the toxins nitrite (to be measured with JBL PROAQUATEST NO2 nitrite) and ammonia (to be measured with JBL PROAQUATEST NH4 ammonium) increase in a short time. Typical effects for this are cloudy water, apathetic behavior of the fish and gasping for air on the water surface.

The lighting duration

Of course we would like to see a lot of our fish. Before work, after work and to go to sleep. As a result, the light should be on from 6:00 a.m. to midnight. This not only causes stress in your animals and the resulting frequent outbreaks of disease, but also unwanted algae growth. Nature should therefore serve as a model for a lighting duration. In the summer months when the hours of sunshine are greatest (longest day: 4:40 a.m. sunrise and 9:36 p.m. sunset - total: 16 hours and 56 minutes) - there is almost 9.3 hours more sunlight than in winter (shortest day : 8:15 a.m. sunrise and 3:54 p.m. sunset - total: 07 hours 39 minutes). If we now enter the compromise in the middle, we come to around 12 hours a day. Therefore, the lighting time in the aquarium should not exceed 10-12 hours. In my private life I only illuminate 6-8 hours a day. A trick that is popular is to introduce a lighting break so that 50% of the lighting time is divided into the morning and 50% into the evening. The break is set to at least 3-4 hours. You can read more about lighting here: Lighting.

The fish are hungry

You throw food into the aquarium and the fish rush to it - they are therefore hungry. If you repeat this procedure, the effect will not change. So are fish always hungry? In principle yes, because fish do not feel satiated. Therefore, you should be fed 1-3 small portions daily and a day of fasting is also okay. Heavy feedings are noticeable due to leftover feed on the ground and heavy water pollution. The conductance and the nitrate content rise rapidly. Over a long period of time, your fish will become fat and have physical problems. We have explained to you what good nutrition for fish looks like: Feeding.

The water change

We aquarists know that a water change means a partial water change. This does not mean the complete cleaning of an aquarium and certainly not other activities such as rinsing out the substrate or cleaning filters. This would inevitably lead to the destruction of the bacterial culture and suddenly to problems with the water values. You can read here how to change the water correctly: Changing the water.


They are really unpopular and drive any aquarist crazy. However, they are part of an intact biosystem - in moderation. It is often referred to as "introduction" and it is believed that it spreads like a disease. "The best thing to do is to remake the aquarium," is then suggested as a solution. The fact that this neither solves the problem in the long term nor eliminates the cause is neglected. Every alga has its cause and can be remedied by correcting the water parameters, lighting or supplying CO2. Adding new plants can also help. A restart is the worst solution in any case. You can read more about successful algae control here: Algae control.


They are not only unpopular in the garden. Snails are often brought in by plants and live on in the aquarium. This is not a problem, because snails are good eaters of leftovers and help "clean up" in the aquarium. Many species are hermaphrodites and can therefore reproduce easily in the aquarium. However, the fact that this only becomes a problem when overfeeding and thus excess food takes place is ignored when there is a plague of snails. Here, too, the use of "snail eaters" or "remaking" is often recommended. In our eyes the worst solution. Instead, the excess food supply should be reduced and the substrate should be cleaned thoroughly. With JBL LimCollect you can collect many snails every day and have permanently eliminated the problem in just a few weeks.

Clear water = good water

You might think that this statement is true, but many toxins are not only invisible, but also odorless. Regular water testing is therefore essential (we recommend once a week). This is the only way to find out whether your fish are doing well and whether problems are looming in the future. We humans therefore go to a blood test every two years, which also provides information about our health, even if we feel well. You can read everything you need to know about water here: Water values.


If you put in too many plants, you won't see the fish, said a customer at the plant. Every aquarist will find out over time that this statement is complete nonsense. Many aquarium inhabitants only develop their courage and show themselves in the most beautiful colors through dense planting. Plants also have a positive effect on the aquarium because they produce oxygen and prevent unwanted algae growth. It is therefore always an advantage to plant at least 50% of the area.

Fertilizing plants

Plants are also hungry and need nutrients (micro and macronutrients), light and CO2 suitable for plants for strong growth. These substances and elements also occur in the wild and are available in sufficient quantities. In an aquarium, even with a large number of fish, there is usually a shortage of these substances. Micronutrients such as iron and CO2 in particular need to be actively added. Of course there are plant species that get by with little CO2, but these also grow more splendidly with an active supply. You can find an overview of the plant selection here: Plant species. A lot of information on the subject of CO2 here: CO2 plant fertilization and fertilization here: fertilization.


Like humans, fish have an immune system. Good nutrition and ideal housing conditions ensure that your animals stay healthy. Unfortunately, it is the two simplest points that are usually the cause of common illnesses. Incorrect water values, expired food, bad food or too long lighting times and noise are a permanent source of stress. But territorial fights and long-term disputes between the fish, due to incorrect stocking planning or a lack of caves and territories can also be a cause. If diseases occur frequently without adding new fish, one of the factors mentioned will be the cause.

After making a purchase, the retailer is often accused of bringing in "diseases", but the fact that the transport was stressful for your fish and that you have strongly deviating water values ​​at home is not taken into account. In the shop all fish were and are still healthy. You should therefore ensure that the transport is quiet and short, as well as a long and slow acclimatization to the new environment. You can find a lot more information about diseases here: diseases.


An aquarium is quiet, there is no shouting or nocturnal rustling. Still, it's not silent. You may hear the faint splashing or whirring of the filter. What calms one down drives the other crazy. If you are sensitive to noise, the aquarium must not be set up in the bedroom. In the living room you will perceive the aquarium as being silent and real aquarists will only sleep peacefully when the even "bubbling" of a membrane pump can be heard. Be sure, there are hardly any quieter animals than fish.


Does it sound negative when you spend time in the aquarium? It is the time devoted to your hobby. Actually, that sounds very positive and you enjoy it. Whether feeding the fish, changing the water or just looking in, you will relax here. An aquarium with a capacity of 60-450 liters will not take up more than 30 minutes a week (that is an average of 4.3 minutes a day) of your time.

Examples of aquariums and their care can be found here:

Jungle aquarium type JBL Rio Pantanal®

Rock reef aquarium type JBL Malawi Rocks®

Goldfish aquarium type JBL Goldfish Paradise®

Aquascaping aquarium type JBL Dreamscape®

I hope that this little overview was helpful to you or that you could find yourself in it. We have linked a lot of additional information to help get the problem under control. Always try to solve one problem at a time. Never change more than one factor and observe the change for at least 7 days. Only then should further aspects be considered. The aquarium hobby requires a little patience and it pays off in the end with colorful fish and strong underwater forests. Do not panic, because as slowly as the problems arose, they also slowly disappear. A hard all-round blow rarely leads to a solution and certainly not to a permanent one.

If you have any questions or suggestions, please use our comment function. I am looking forward to your feedback.