Popular Species

Owning an aquarium with one, two or many healthy, jewel-toned tropical fish is a delight. Just watching how fish interact with each other and their environment can provide hours of pleasure.

Though there are hundreds of fish that can thrive in an aquarium, some are more popular than others, whether because of their beauty or the ease of their care. Here are some popular species:


These fish get their name because the lower rays of the male’s tail fin are drawn out into a sword that can be as long as his body. They come in many color variations, from olive green with a yellow belly, to red or orange with black or orange fins.

The female swordtail is a bit bigger and bulkier than the male. She can grow up to 4 3/4 inches long, while he can grow up to 3 1/4 inches long without his tail.

Swordtails prefer water that’s between 72 and 73 degrees Fahrenheit and has a pH of 7 to 8. They thrive in hard water and bright light. They need room to swim around, are compatible with other live-bearing fish and take both live and dried food. Swordtails reproduce fairly easily in captivity, but the problem is that they eat their young. Experts recommend that a day or so before the female gives birth the adults be put in a breeding trap that has holes big enough for the fry to escape.


There are many varieties of these striped, deep-bodied little fish from Southeast Asia. Barbs need lots of space to swim around, and the water should be gently flowing, soft and refreshed regularly. They do best in a well-lit aquarium but also appreciate a cover of floating plants. The substrate at the bottom of the tank should incorporate some humus.

Barbs are omnivorous and need lots of food, and the ease of their reproduction differs from one species to the other. The black ruby barb reproduces easily but the tiger barb doesn’t unless the water temperature is kept high. Reproduction by the Chinese, Sumatra and cherry barb are somewhat hit and miss. All barbs lay eggs and get along with schooling fish of similar size, which can be up to 3 inches long.

Betta Splendens

This is the fascinating Siamese fighting fish. This fish, which grows up to 2 1/2 inches long, has a slender body with compressed sides. The males are bred for their vivid colors, long, pointed pelvic fins and large, wavy, beautiful tail, dorsal and anal fins. The females are fairly drab.

Bettas prefer warm water of at least 77 degrees F. If the owner wants to stimulate breeding, they should raise the temperature to about 86 degrees F. The fish doesn’t care too much about the pH of the water as long as it’s not too hard. It prefers an aquarium with good lighting, a medium to thick amount of vegetation and a soft substrate. The tank should be covered because bettas have a tendency to jump out. It prefers live food but will happily eat dried.

Betta males are called fighting fish for a reason. They’re very aggressive toward one another and even aggressive toward the mothers of their children. Because of this, a female needs to be removed from the male’s tank after she’s laid her eggs. The male supports the eggs in bubble nests he makes among the vegetation. The eggs hatch after a day or so, and the male should be removed three days after this, for he’ll become aggressive toward his own young.

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