Briefly about the subject
One simple rule: the larger aquarium with many easy-to-grow plants and the fewer fish in it - the less often cleaning! There is a simple rule to count minimum size of aquarium: 2 liters of water should be planned for every centimeter of each adult fish.
And below in details
The fact is that small aquarium requires much more time and actions to maintain a good condition and a beautiful appearance. Fishes and other aquarium inhabitants spoil the water with their waste toxically products. Toxic products normally refines by nitrifying bacteria. In small aquarium the less space for bacteria and less clean water capacity.
In addition, due to an excess of nutrients, harmful algae grow faster. The water becomes cloudy and blooms. Plants cannot compete with algae due to the lack of space and their quantity.
As a result in smaller aquariums the water will be fully deteriorated faster and owner will have to clean aquarium and change water more often.
In this state, small overfeeding or untimely cleaning of a small aquarium lead to rapid deterioration of water. Fishes get poisoned, then get sick and, unfortunately, in most cases die.
Treatment of fish is very difficult, requires constant monitoring, purchase of medicines and rarely leads to recovery. All this also greatly spoils the mood and discourages the desire to keep fish.
And in opposite bigger aquarium with big quantity of plants and appropriate quantity of fishes can’t be cleaned for very long time:
1. big capacity of fresh water dissolves toxic substances and does not allow their concentration to increase quickly;
2. there is enough place in big aquarium for big quantity of soil and plants an so enough nitrifying bacteria can refine more toxics;
3. furthermore, plants will consume waste, harmful algae will not grow and water will not bloom.
In general, when determining the volume of aquarium, it is necessary to take into account the types and number of fishes and use of filter. And about this in below!
Maintenance and water filtering
Aquarium filters, especially external ones, purify water even in small aquariums and can extend the time between cleaning and changing water.
External filter purifies the water due to the nitrifying bacteria live on the filter materials. However, each filter designed for a certain volume of water and it will not solve all the problems in small aquariums:
1. normally bacterial nitrogen cycle ensures the processing of the most toxic ammonia into nitrates which must be removed from aquarium;
2. due to evaporation the hardness of water is increasing and it also requires water replacement.
Correct determination of aquarium volume
It is advisable to choose the size of the aquarium in accordance with the available space in the apartment or house. In addition, it is necessary to provide a place for maintenance:
1. opportunities for soil siphoning,
2. pull out the filter for cleaning,
3. clean the glass from green algae,
4. water replacement.
As a rule, this is 0.5 - 1 meter in front of the front wall
Fishes are also an important factor. If you have space for a small 30 - 50 liters aquarium, then you will be able to keep only small fish species: guppies, tetras, otocinclus catfishes, Heterandria formosa, microassemblies, as well as dwarf forms of some fish species.
Larger fish, such as goldfish, cichlids, large barbuses need a volume of 100 - 150 liters and up to unlimited, depending on the number of fish.
And there are fishes that grow up to 1-2 meters, for which the size of the aquarium is measured in tons!
There is a formula for roughly calculation the minimum volume, required for one fish. For every centimeter of an ADULT fish, 2 liters of water are needed. Respectively, if several fish are planned, it is necessary to calculate the required volume for each and sum up the result. The sizes of adult fish are indicated in the description of the fish in the fish section.