First of all, please do some research before you buy any fish. Always remember that, newly set up aquarium needs to be cycled. This is called nitrogen cycle. If the water is not nitrogen cycled, then the fishes will die for sure. For more information about the nitrogen cycle visit YouTube, there are many videos on this topic. There are many more reasons for fish to die. For example:

1. Aquarium water parameter :

The water parameters that is pH (volume of hydrogen ion), GH (general hardness), KH (carbonate hardness), ammonia, nitrite, nitrate etc. are the main water body compositions. These parameters may affect your fishes. For this reason, always try to study your water parameters first then go for the suitable fish for such water parameters. Some fishes are hardy that means, they can leave in various ranges of water parameters.

2. Aquarium water temperature :

There are some fishes who live in cold water without any problem, but if you put them in warm water they will show some deficiencies. This is just because they are not in their natural habitat, their natural water parameters. Please do remember, every fish have some limitation for water parameters and the environment of your aquarium.

The above explanation is just an introductory knowledge we are providing you, now let’s come to the question.

By reading above information, we think you have some hints about why your fishes died in your newly set up aquarium. Without nitrogen cycle, over 90% of fishes will die. Hardy fishes also need your aquarium water aged for atleast a week or two. After two weeks, you can check the water parameters by using API master test kit. We highly recommend API test kit because, it has entire range of water test for our purpose. If test result shows the good parameters, you can find the information about appropriate water parameters in the book provided. If the results are good then, your tank is ready to introduce your fishes.

By following such method, your fish will never die because of new aquarium syndrome. Unless, you pick up healthy fishes from the source.

Aquarium without filter is just like human without lungs. As per our knowledge, every aquarium should have filter in it. Filter also dilutes oxygen in water and even carbon-di-oxide which is very useful for plants in their growth.

Excess amount of food, fish waste, dying leaf of plants are the sources of ammonia. Ammonia is a very hazardous substance for human and for fishes also. If in any aquarium the value of ammonia is more than 0.1% PPM ( part per million) then it is lethal for your fishes. This tiny level of ammonia is alarming level and will have its impact on your fishes.

In our aquarium, filter is the one of the important instrument. Filter always maintain your aquarium water quality. The main role of the filter in your aquatic system is to give home to beneficial bacteria.

What is Nitrogen Cycle ?

There are two types of nitrifying bacteria. One is Nitrosomonas Europa and the other is Nitrobacter. Nitrosomonas Europa consume ammonia as its food source. The byproduct of Nitrosomonas Europa is nitrite. The another bacteria called Nitrobacter will consume this nitrite and its by product is nitrate. As compared to Ammonia, Nitrate is less harmful for fishes. If you have plants in your aquarium, this nitrate will be consume by them. In short, this is what the nitrogen cycle is.

We think this is enough information about nitrogen cycle given in this section. Why are we giving this information to you ? Because this is the base of the question that, why you should use filter in every aquarium. Filter provide residing area for these bacteria. Water passes through filter circulation and any excess amount of ammonia will be consumed by this bacteria. Now, your tank will get better and better.

Let’s calculate the aquarium volume. suppose we have 3ft x 18in x 18in fish tank. First, measure your aquarium size i.e. length, width and height in inches (36 x 18 x 18). After getting the correct measurements, multiply them together and divide by 231 (36 x 18 x 18 / 231) so that, you can get the water volume in gallons (50.49 Gal.).

Second, after getting water volume in gallon, multiply it by 3.785 (50.49 x 3.785). This is how you can get the aquarium water volume in litres (191.11 L).

After following these two steps, multiply the litre value with 6 (191.11 x 6). Your aquarium water should be filtered for atleast 6 times per hour. This is how, you come to know the right filter capacity for your aquarium (1146 l/h). In this case, your filter should be around 1150 to 1200 l/h. In a suggestion, fish tank from 3ft upwards should have canister filter to get  nice circulation and clear water.

Nature have its own ecosystem. Rivers and streams are free flowing and there is no barrier to stop the water from flowing. The aquarium at our home is nothing but to mimic the nature in some different levels. Aquarium have stagnant water body. You don’t have any ability like nature to bring fresh flowing water every time. Constant changing of water in nature is the key.

If you don’t change aquarium water more than a week then it will get some algae issue. The main reason for the algae to bloom in your aquarium is the high levels of Ammonia, nitrite and nitrate. To have clean water for your fishes and plants you should keep changing your water at least once in a week. This practice gives you better results of your fish health and nicely growing plants. In short, water change is very necessary.

Every aquarium need light. The amount of light may differ by tank size. There is also one important thing to consider that if you have a planted tank the amount of light should be high as compared to low tech aquarium, a tank without plants or low light demanding plants. You should have proper light in your tank because it can cause algae issues. It can even affect the growth of plants and their photosynthesis process.

There are many types of aquarium lights for example, LED, metal halide and t5 HO tube. Choose any of these type as per your requirement but make sure that the light and the type of aquarium (low tech and high tech) should be compatible with each other.

You should feed your fish twice in a day. The amount of food depends upon your fish type and its size. You should feed your fish the right amount of food which they can consume in 2 minutes. Excess food can create dropsy in fish, tank gets dirty and even algae can increase. Proper and healthy food will keep your fish healthy and there body colour will enhance naturally.

Aeration is very much necessary in your tank. It supplies outside oxygen (gaseous exchange) in the water and even dilute CO2. If you have planted tank then, it is not necessary to have the aeration unit because plants itself releases the oxygen in the water which is useful for fish. That is why no extra aeration is necessary in this kind of tank.

The other thing to get into consideration is, if your tank volume is more than the filter capacity then you should have the aeration unit.

Nowadays, the artistic aquarium work is called aquascape is more in trend showing the necessity of aeration useless. The state of the art filters are capable of gaseous exchange and have surface agitation ability. So in short, we don’t need aeration unit separately for any of the aquarium.