Fish: Animal behaviour and problems.

      General information

      Fishes are poikilotherm animals living in the water, making       use of their gills to breathe. Their body is designed in a form       that allows to surmount the resistance of the water in the       easiest way. Their gills correspond to the legs of the       quadrupeds. The skin is normally covered with a lot of scales.

      With about 20'000 species they represent the largest part       group of the vertebrates. They live in clear mountain streams,       in lakes and ponds, in the upper and lower reaches of the                                                                                        rivers, on costal areas and in the oceans. One divides the fishes up to both classes of the bony fishes and the cartilaginous fishes.

Social behaviour

Since in the aquarium it comes to a mixture of all kinds of fancy fishes, one can rather talk of an interspecies animal behaviour. It makes sense that the mixing of quiet, lively, aggressive, placid and secluded fishes, fishes living on the bottom or fishes living on the surface, produce a multitude of social structures. In principle one has to pay attention that the "domestic peace" is not disturbed by thugs and too playful "pluckers". As an example some behaviour patterns: Guppies are lively swimmers and like to live in groups of 4 to 6 fellow species. Fishes of paradise can become a nuisance as troublemakers for other, slowly moving fishes. That is why it is important to keep only a pair of them. Skalares seek a corner in the aquarium as their territory and defend it.

Neon fishes (paracheirodon innesi), harlequin rasboras (rasbora heteromorpha) or also zebra barbels (brachydanio rerio) like to live in large shoals. The antenna catfish is as "window cleaner" a typical loner who, however, absolutely needs an own cave which he defends against intruders. This way every species has its own characteristic for its social behaviour.

Behavioural disturbances

A great many things that from the fish owners' point of view look like an abnormal behaviour or at least represent an undesired behaviour, have to be attributed to wrong socialization. Insistent males: Increase the number of females in the group. Predatory fishes who eat up other fishes: Wrong combinantion. Defending the territory: A normal behaviour of certain species. Etc.

Undesirable behaviour

When bigger fishes eat up the small aquarium inhabitants, when insistent males don't stop bothering the females, when certain fishes pluck at other fishes fins, this is not an abnormal behaviour of the fishes but in most cases insufficient knowlege of the fish owner. The truth is: Aquaristic is a very extensive specialist field and already the successful socialization of different groups of fishes requires knowledge and professionalism. The same phenomenon can also be observed in bird aviaries. Not everybody suits everybody! Even the filling within the same fish species is an art. One might fill just 1 male with 4 females. "Undesired behaviour" can be avoided!