If you need to give an example of popular opinion, you can give a judgment about the need for a hungry day, as the unconditional law of proper feeding of aquarium fish.
The source of the advice of professional aquarists to newcomers about the introduction of a hungry day is the conviction that a novice aquarist will definitely overfeed his pets, therefore it is rational to stop organic stuffing into the aquarium water for at least a day.
From the point of view of the normalization of the hydrochemical composition of aquarium water, this does not prove its usefulness in practice. On the contrary, the accumulation of phosphates and nitrates will continue with no less speed, the oxidizability of water will continue to increase rapidly.
The main postulate claiming the need to introduce a hungry day. an indication of cold-blooded representatives of the class of fish. Allegedly, this feature causes the need for smaller amounts of energy and therefore it will be useful for aquarium fish, it will give an opportunity to get rid of slags.
First, slags are wastes from metallurgical processes, and not “waste” physiological processes, each of which has its own name and is removed from the body naturally, which is not affected by hunger, but by the state of the systems responsible for such processes.
Secondly, personally, I have not seen a single fish, perched in the lotus position and flew away to nirvana. Probably, the fish do not resort to such practices and do not refuse in natural conditions once a week from food. They do not know about their cold blood and that they need less energy. Therefore, they rampantly spend this energy, obtained from food, on the course of biochemical cycles that provide energy for the synthesis of cells of the immune system, respiration, movement the list is endless.
In fact, a hungry day is not only the most powerful negative stress, when the inhabitants of the aquarium suddenly encounter the complete absence of previously regularly arriving food.
Many aquarium fish that have a long intestine and a mixed type of food, consuming food throughout the daylight hours, are strictly contraindicated. These fish for the normal functioning of the body, requires a uniform filling of the intestine along its entire length.
Among the species for which the answer to the question "How much can you not feed aquarium fish?". will be "not at all". such as:
– all kinds of barbs;
– labyrinths (hungry days are especially harmful for lalius);
– Variants of goldfish;
– viviparous fish (especially breeding species);
– neons (these fish naturally consume a small amount of feed, which must be taken into account when feeding them)
Hunger days are also harmful to active fish, and therefore needing a lot of energy from food. For example, Malawian cichlids, cichlids from Lake Tanganyika.
Hungry days for Cichl are one of the reasons for the weakening of the body’s resistance to hexamitosis. A hungry day for an angelfish. provoking the disease mycobacteriosis. In addition, if we talk about scalars. if such fish are kept with neons or other small species, then in hungry days they start trying to catch smaller neighbors. If this succeeds, the hunt will continue in the days of abundant feeding.
Instead of a hungry day, a fasting day is used, when the feeding ration is built on the basis of granules with a high content of vegetable components, especially spirulina.