Children's World - Pets - Fish SI

Children's World - Pets - Fish

Rainbow fish – Guppy

(Poecilia reticulata) 

Rainbow fish originates from Middle and South America and is among most frequent tropical fishes bred in aquariums. It was brought to Europe during 20th century. It belongs to tropical fishes because it needs heated water in aquarium (26 °C), pretty hard and can also live in brackish water. Rainbow fishes bear live babies and together with some other families, belong to live-bearing fishes. They feed on water insects' larvae, and if the insects are small they eat also adult insects. Males are from 1.5 to 3 cm long, and females from 3 to 5 cm. Males are much nicer in colours than females, partly in order that they might attract them while the other reason is to bait eventual chasers.

The breeding of the Rainbow fish in aquariums began during 20th century and a number of varieties of the species were created in different colours, tail and body shapes. Rainbow fish is very adaptable, so it is relatively easy to breed it also in a small aquarium containing water of lower quality whose temperature is also not too important in amateur breeding. It is sufficient to have an aquarium of at least 40 litres and some water plants in it and put future parents together taking care that there are not too many males in aquarium. By chasing one another away from the female the males actually do not succeed to fertilize her. In that period it is good to offer them live or frozen food (daphnia, tubiflex, mosquito larvae etc.), because the number of  young fishes will thus be higher and more of them  will survive hiding behind plants, since after birth they are chased by all (including parents) who want to eat them. Since rainbow fishes become sexually mature in short time, we can have several generations of them in one year. However, because of mating between kin, their look tends to return to natural, and such rainbow fishes are not too attractive.

Rainbow fish is the most frequently amateur bred aquarium inhabitant and attracts many people just with the multiplicity of its colours and varieties.   

Siamese fighting fish

(Betta splendens)

Siamese fighting fish originates from Southeast Asia and is a characteristic example of lungfish, which apart from gills have another organ for breathing, the so called labyrinth. In nature they need it in order to survive the lack of oxygen in water and during drought.  These fishes in nature often live in rice fields and sometimes find themselves on dry land. Then they lie in mud and breathe oxygen from atmosphere.

Most often we keep in aquariums male fishes because they are more colourful and have bigger fins than female fishes.  By breeding a variety of colours and their combinations were created. This fishes got their name by the fact that they are very territorial and defend their part of aquarium or a water plant bush in which they dwell. In nature such fights end with the withdrawal of the weaker, but in aquarium, because of limited space, they most often end with the death of one of the rivals. In Thailand they used to organise until recently the fights of these fishes and betting, but during last years this was fortunately forbidden. So, in aquarium we can keep just one male Siamese fighting fish, since otherwise they would fight one another.  Also, other kinds of fish in aquarium cannot have long fins because this provokes the fighting fish to fighting.  Though, Siamese fighting fishes are not too demanding, so in several smaller aquariums we can keep one of them in each and enjoy their many colours and varieties. In the world, and recently also in our country, competitions and exhibitions of Siamese fighting fishes are organised, which show how beautiful and attractive they are for breeding.

In nature they feed on live food (larvae and adult water insects), and in aquariums they are used to food in form of small leaves.

Their reproduction in aquarium is also very interesting, since - like some other kinds of lungfish - they build a nest from foam which floats on water surface. A female and a male then lay together spawn into it, which the male then guards until the fishes hatch. If the aquarium is small, the female has to be removed to avoid problems.   

Siamese fighting fish is indeed a nice example of variety and beauty of animal species on Earth.   


(Pterophyllum scalare)

Angelfish originates from South America, and lives in Amazon River, its tributaries and in some lakes.  It was brought to Europe in the 20th century when its breeding in aquariums began. Angelfish is a monogamy fish and a pair remains together for the whole life. Because of their elegance and calmness it became one of the most often bred species in aquariums. In nature angelfish lives in soft and slightly acid water of 27 °C, but bred species got accustomed also to our harder and more alkaline water. They feed on live food, so that it is not good to put smaller fishes into aquarium because they will eat them.

Angelfishes are good parents, as well as other species from the cichlid family, but for spawn they need a greater aquarium (of a volume of more than 100 L) in which a pair will choose a place to lay spawn. This is most often a bigger water plant leaf.  After laying pawn, the pair guards it and defends from predators and after 36 to 48 hours the larvae hatch, under protection of both parents.  Since angelfishes have been bred for long time in aquariums, with time they lose their parental instinct so that it can happen that a male chases female away from the offspring. Therefore, attention should be paid to it and the female should be put to safety it the male chases her.

Small fishes eat live food, like artemia or daphnia, which we can ourselves breed or buy frozen. Also, when they get a bit older, they will be happy with ready-made food in the form of small leaves or granules.

If it is not important for us to breed small fishes, the angelfishes are a nice decoration of a mixed aquarium, provided that there are no fishes from the genus Barbus inside. These fishes nibble on angelfish fins and make them nervous; and just the calmness and elegant swimming are the main features of angelfishes.

Over many years of breeding numerous mutations of colours and body designs have been created. All this classifies angelfishes among the leading inhabitants of aquariums throughout the world and the number of their fans is from day to day greater. 


(Carassius auratus)

Goldfish is among the most frequent pets in the world and the most favourite one in aquariums. It originates from Eastern Asia while first documents on its breeding originate from China, from the 3rd century. At the beginning of the 17th century seafarer brought them to Europe where their breeding began at first in garden lakes, and then also in bowls.  All this contributed to today’s diversity in colours so that today goldfishes can be white, yellow, orange, red, brown and even completely black.  Equally, the shapes of their body, head, eyes, fins and tail come in many variants. So, we have common goldfish (short body and double tail), telescope goldfish (pop-eye and double tail), red riding hood (white with red point on head), pearl goldfish (scales in the shape of pearls), lions head (with outgrowths on head), as well as all of them already mentioned and many others with normal or prolonged fins (this shape is called comet or butterfly, if the tails are double).

Goldfish is classified among cold-water fish, which means that it does not demand a precise water temperature and also no special hardness or chemical composition of water. Because of these features goldfish is the most common in home aquariums, since it needs for life just several tens of litres of water in any kind of bowl. During many yeas goldfishes were agonized in small, round glass bowls containing just a few litres of water but in the last decade more and more states forbid such way of keeping goldfishes.

They reproduce by spawning and a female can lay up to several thousand sticky fish eggs (depending on its size, and it can grow up to 30 cm or more). After fertilisation the eggs stick to water plants and after several days fishes hatch from them. The feed on larvae and plant food and grow fast in first weeks.

Goldfish is the one “fulfilling” three wishes, but also without putting questions it will bring us joy and cheerfulness if we keep it as a pet. 

Boris Cebović
           Small Animal Breeder

Technical Details

Issue Date: 22.02.2016
Designer: Lidija Novosel and Adam Peter Maguire, designers from Zagreb
Printer: Zrinski d.d., Čakovec
Process: Multicolor Offset
Colours: 4 Colours
Size: 35.5 x 35.5 mm
Values: 3.10 HRK x 4