Some are as big as your hand, others the size of a thumb nail. Most of them come from hot tropical countries. They have been bred in captivity to be displayed in aquariums. Let us look at some of the interesting aquarium fish and observe their characteristics..The SwordtailThe swordtail has a long growth like a sword on its tail, which is how it got its name. It lives in small ponds in South America. When it is swimming, it uses its sword like a rudder, to steer..GuppiesYou don’t know which way to look when you see a shoal of multi-coloured guppies. Little and lively, they are always on the move..Black MollyThere is nothing blacker than the Black Molly in the whole aquarium. Its little ones are also black and lively. As soon as they are born they set off to look for food..Golden GouramiThe golden gourami has long thin whiskers in place of breast fins. When it finds something interesting, it puts out its whiskers, as if they were hands, to feel what it is: the weeds, the glass walls and the little snails in the aquarium, and if it is another fish, the golden gourami pats it with its whiskers as though in greeting..The Glass fishThe fish is so transparent that you can even see its skeleton. It is hard to make out this fish in water and in the weeds you cannot see it at all. A sharp-toothed enemy will swim past and be completely puzzled, for there is a floating skeleton, but no fish to be seen. Deciding that this must be a fish that somebody else has already picked clean, the hunter simply swims past. The glass fish then swims away to find a worm for its dinner. This is no easy task in the river, as opposed to the aquarium where live worms are fed in from above..Jewel FishThe Jewel fish swim quietly and self-importantly around the aquarium. When the time comes to breed, they choose their spot, deposit their roe on a stone and stand guard over it, letting no other fish come near. They leave their post only to eat. The father takes his turn, until the mother comes back, and so they stand guard day and night, like loving parents..LyretailThis fish looks like an arrow, and swims as fast as an arrow in flight. Its fins are both a rudder and oars, and sometimes a brake as well. As soon as it wants to stop, it fans them out and stops dead; its brakes are working. They often save its life. When chased by a predator, it dives into the weeds and stops dead there, while the enemy keeps going, puzzled by the disappearance of the lyretail. And so it sets off in pursuit of some other fish..HeadstanderThe headstander spends all its time on the head. This is the most convenient position for rummaging in the mud for worms. It is so used to this position that even when full stays in it. And so we joke that it is the “cleverest fish of all”, because its head is so heavy that it weighs it down..Discus FishThese fish are flat, and they are round, like pancakes. They are called Discus fish making doting parents. While their young ones are still bad swimmers, they help then along. For this purpose the young have special threads to attach them to the parent’s body..Angel fishThe angel fish live in the Amazon river, among the thick growing bullrushes. But the Angel fish swim freely in and out, for their bodies are completely flat..Diamond fishThey are called diamond because they sparkle will all the colours of the rainbow just like diamonds. Quick and lively, they dart about flashing as if a handful of jewels has been thrown into the water..Emperor TetraIf you are a keen observer, you will notice that this fish has a tail in the shape of a crown. Because of its ‘crown’ it is called the Emperor Tetra..Lemon TetraThis pale-yellow fish with red eyes is very beautiful against a background of green weeds. Lemon Tretra is no bigger than a coin, but quick and lively. Trying to catch it is no easy matter, for it knows its way perfectly in the underwater maze of weeds. If it were not so nimble, its larger enemies would eat it up. But this fish manages to survive and has come to grace our aquarium..Congo TetraThe fish comes from tropical Africa. In the River Congo, it had many enemies to escape from, so it became a fast swimmer. Now it has come to live in the aquarium. It darts up and down like a motor-boat, so fast that you cannot get a proper look at it until it stops for a rest..Harlequin FishEveryone took a liking to the Harlequin fish when it first arrived from Indonesia. But nobody managed to get it breed in captivity; the roe always perished before it hatched out. Then it work when it was bred in rainwater. The young ones hatched out of the eggs and grew into big ones, and that was how people learnt to breed it..Dwarf GouramiThe Dwarf Gourami is a very elegant fish. It dark-blue breast looks like a shirt under a jacket, and the jacket itself is all red and light-blue checks. It gets this beautiful colouring only when it is fully-grown and has learnt to swim fast. When it is small it is quite different: grey and plain. to make it more difficult for its enemies to see..Black RubyThe Black Ruby is a fish with a big appetite. When you drop food into the water, the Black Ruby is on the spot at once. It is probably due to the fact that it eats so much that it is such a fast swimmer..Sumatran Tiger BarbThe fish comes from Sumatra Island of Indonesia. The Tiger Barb is yellow, with black stripes across the body. This colouring helps it to hide from its enemies. It goes down to the sand at the bottom and takes up a position among the stems of the weeds there, it merges with its surroundings.
