"The Amazon River system in South America is home to a dazzling variety of small, colorful, schooling fish known as Tetras. They are justly popular aquarium fish with their glittering colors and synchronized schooling behavior. However, few fish keepers keep them properly and in sympathetic surroundings that shows them at their best. In this post, I'll show you how to keep these beautiful little fish beautifully.
First, the origin of the common name; Tetra. When explorers brought back fish from the Amazon region in the teens, 20's and 30's, science lumped them all, big and small, into the Genus Tetragonopterus based on the number and shape of their teeth; which all Tetras have, from little Neon Tetras to the fearsome Piranha. That Genus is now almost totally vacated, and applies to only two fish I know of; T. argentus and T. chalceus, both ovoid, silvery Tetras.
The vast majority of Tetras available in the hobby do best in moderately soft, pH 6.8 water at 75 to 78 degrees, though nearly all are adaptable to a point. They are rarely as colorful in hard water and at high pH, and are more prone to disease in such conditions. What they like are well-planted tanks with driftwood and stones. They don't like very bright tanks, so floating plants should be provided over the main viewing area so the light is filtered. I primarily use Amazon Frogbit (Limnobium laevigatum) for this purpose, though any floating species would do. Tetras look most attractive and colorful swimming through the shadows and light. Dark-colored substrates intensifies their colors.
Tetras are all long-lived, especially for little fish. You should expect at least five years with your charges, though with some species, you could enjoy them for more than 10 years.
One item that many overlook is that Tetras are very much schooling fish, thus for their continued health, one is obligated to keep them so. How many? In a well planted, established and filtered 20 gallon, 48 neon-sized Tetras easily. In a larger tank, say a 75 for example, it's not at all difficult to keep 10 dozen.
Why? Because the neon-sized Tetras impinge so very little on water quality.
Feeding is another matter. Tetras have teeth, meaning their diet should contain meaty items primarily, with vegetative foods a smaller percentage. ALL of them do better and are more active, colorful and vivacious if fed live foods two or three times a week. Daphnia pulex is a favorite, though they do like wingless Dropsilia species fruit flies. The small Tetras can choke on things like white worms, so they should be cut into halves or thirds before feeding. A good pelleted food should be the staple, with vegetative foods, like Spirolina flakes, a couple times a week. Live food (if available and clean) as a substitute for a meal two or three times a week.
Feeding should be small meals given often, rather than one large meal a day, as Tetras are nibblers, not gorgers. As they are fast eaters, no more than they can finish in a minute three to five times a day.
So, give them the sympathetic surrounding of a soft, slightly acid well planted tank coupled with a good diet, and your Tetra tank will be the envy of all who view it."
This article focuses on the South American Tetras where the waters are warm. Therefore most Tetras do better with warmer tank water however, please research before you buy as with the Neon's they do much better with cooler water as low as around 72 degrees and have a much longer life span with the cooler temps.