They’re small, colorful, peaceful, and best of all, they always stick together.
This month, The Wild Side pays homage to one of the most revered Fish groups of all, the Tetras. They’re so popular that the biggest brand of aquarium and pond products, Tetra Werke (which means “The Tetra Company” in German), still bears their name.
SPACED-OUT CELEBS
Individually, most Tetras are meek and seem to be constantly spaced out. They don’t have the personality of larger Fishes like Cichlids, the virility of livebearers or the sheer “oomph” of showpieces like Discus.
What they lack individually, though, they more than make up for in numbers. A gleaming shoal of Cardinal Tetras, especially set against a planted or dark background, is a sight glorious enough to make even casual onlookers pause. Even humdrum species like the Blackline Tail Tetra can form downright hypnotic shoaling patterns when stocked by the dozen.
Tiktok and Instagram are a swim with these “Tetrarrific” reels that help make Tetras so popular.
MEET THE TETRA FAMILY
All Tetras are Characins, which is a huge family of Fishes that belong to the order Characiformes. A study on the “Phylogeny and Classification of Neotropical Fish”, published by Luiz Roberto Malabarba and Maria Claudia Malabarba in 2020, revealed that there are at least 2200 Characiforms, ranging from the massive, six-foot-long Goliath TigerFish to the various Piranha species that can reputedly strip Cattle to the bone in minutes.
Tetras may be the order’s tiniest members, but again, what they lack in size, they make up for in numbers, comprising an impressive 800 of the 2200 Characiform species.
What Tetras lack in size, they make up for in numbers: They make up an impressive 800 of the 2200 Characiform species.
FEW AQUARIUM CANDIDATES
Like most Fish families, few representatives ever make it to people’s homes. Just 150 or so of the 800 known Tetra species cruise among planted tanks. Most species just aren’t too colorful, grow too large, are hard to keep, or are too infrequently collected to become hobby mainstays.
The Tetras generally kept in aquaria grow just one or two inches, are colorful, and are hardy enough to thrive under most conditions. Most have just one or two distinguishing marks: a spot here, a stripe there.
SMALL AND ADAPTABLE
The great majority of Tetras– some 700 species – hail from the richly forested waterways of South America, with another 120 or so representatives from Africa.
The first Tetras flooded the fledgling aquarium industry almost a century ago, when people still used metal-framed aquaria with stone bases. As exotic then as they are now, Neon Tetras were shipped from the Amazon Basin to North America and Europe in the 1930s, delighting millions of people.
Since then, many other Tetras have become mainstays of planted, community, and biotope tanks. As they are small, peaceful, affordable and adaptable, Tetras make excellent companion Fishes for most community tanks, able to get along with everything from small Shrimp to frisky Tiger Barbs.
12 ALL-TIME TETRA GREATS
Animal Scene readers, let’s meet a dozen of the all-time Tetra greats.
NEON TETRA (Paracheirodon innesi)
This is the first Tetra to reach most people, and they’ve been a cornerstone of the aquarium hobby for nearly a hundred years. Their horizontal neon blue stripe and even red and silver keel matches the vibrance of reef Fishes.
The Neon Tetra is affordable, relatively hardy, and comes in several color and fin morphs, with the species having been bred in captivity for decades.
Watch out for the dreaded “Neon Tetra Disease”, evidenced by pale, gangrenous-looking body portions. All Fishes with this affliction are goners.
CARDINAL TETRA (Paracheirodon axelrodi)
Proving that just a little more red goes a long way, the more expensive, prettier, and harder-to-keep cousin of the Neon Tetra grows slightly larger but is among the most beautiful of the world’s freshwater Fishes.
In contrast to Neon Tetras, most Cardinal Tetras are collected wild from shallow pools and sustain the seasonal livelihoods of small-scale freshwater fishers in South America.
GLOWLIGHT TETRA (Hemigrammus erythrozonus)
Perhaps a close third in beauty to Neon and Cardinal Tetras, the glowing orange stripes of a shoal of Glowlight Tetras looks absolutely stunning, especially against a plain dark backdrop.
They are easy to keep and rarely bother other tank inhabitants.
RUMMY NOSE TETRA (Petitella rhodostoma)
These tiny torpedo-shaped beauties swim fast and are most beautiful in a shoal of ten or so. Their glowing red snouts are set off by the tasteful black and white patterns on their tails.
Rummy Nose Tetras have several lookalikes, but they all require stable, aged water, lots of plants, and quiet tankmates to thrive.
BLACK SKIRT TETRA (Gymnocorymbus ternetzi)
Some Tetras quietly accentuate the beauty of others. This is one of the group’s more plainly colored members: grey and black painted on a disc-shaped palette, set off by long flowing fins.
A few of these gentle black beauties will make your more active and colorful Tetras stand out.
PENGUIN TETRA (Thayeria boehlke)
Possibly the most “spaced-out” freshwater Fishes you’ll ever meet, they spend most of their time in what I call the “Penguin Tetra Trance”: staying in place, with minimal fin movements (similar to many saltwater Cardinalfish).
The above behavior of Penguin Tetras carries a unique charm. Make sure to keep them only with gentle species.
BLACKLINE TAIL TETRA (Moenkhausia costae)
Though plainly colored, this relative newcomer is becoming more and more popular, being kept in dense populations in planted tanks. I’ve seen tanks all over the world stocked with over a hundred of these synchronized-swimming silver Fishes.
SERPAE TETRA (Hyphessobrycon eques)
This mid-sized Tetra can be a bit aggressive but is one of the most beautiful orange Fishes in the market. Feed your shoal color-enhancing food like Tetra Ruby to make these living jewels glow.
Some Serpaes also feature black-comma or diamond-like markings on their flanks.
EMBER TETRA (Hyphessobrycon amandae)
Among the 800 or so Tetra species, I heartily vote this as the pound-for-pound “tiny tank” champ. Smaller than most Tetras, they grow less than an inch but are beautiful (especially when fed color-enhancing food), hardy to the extreme, completely harmless, and have not once caused me any kind of trouble in the 30 years I’ve been caring for Fishes.
These little guys are real winners.
LEMON TETRA (Hyphessobrycon pulchripinnis)
Need a dash of yellow? Then, a shoal of Lemon Tetras is all you need.
Among the first Tetras to be kept in captivity, Lemon Tetras have dazzled folks for a hundred years, with their yellow bodies, glowing red eyes, and black fins accentuating the plantwork.
BLEEDING HEART TETRA (Hyphessobrycon erythrostigma)
An “old-school” beauty, this Tetra grows larger than most, reaching around three inches. They command viewers’ attention – and a good price –wherever they are cared for.
The Bleeding Heart Tetra is one of the very few Tetras I would consider “showpiece Fish” – able to become the centerpiece of a planted Tetra tank.
CONGO TETRA (Phenacogrammus interrupts)
The sole African Tetra on our list looks plain from afar but has large, gleaming, iridescent scales when sidelit, much like Dwarf Neon RainbowFish.
These mid-sized Fishes can complement any community tank to razzle and dazzle viewers.
The list can keep on swimming to fill entire volumes, but the tantalizing Tetras above are but a sampling of the vast number of Tetra species you’re likely to run into someday.
There are obscure ones like the Lizard Tetra, transparent members like the Mountain Crystal Tetra, and even those who don’t look like Tetras, like the Sailfin Tetra. Every now and then, a batch of rare, wild-caught Tetras will find their way to your local store, so keep your eyes and wallets peeled.
Tetras, along with Danios, also comprise the majority of the “GloFish” becoming more and more popular nowadays. (Grab a copy of Animal Scene’s September 2020 to read our feature on them.)
MAKING SURE TETRAS THRIVE
Tetra care is relatively straightforward. As most species hail from the Amazon and the other river systems of South America, they do best in slightly acidic water, with a gentle current and loads of plants. Feed them sparingly and keep them in shoals of at least six Fishes, but the more, the merrier.
Remember that Tetras are prey, like the Antelope and Zebra of the African savannah. If you don’t want your Tetra schools to become Tetra snacks, then don’t mix them with large predators like Arowana, Angelfish, or Discus, all of whom literally eat Tetras for breakfast in their home waters.
Tiny jewels that quietly cruise through our planted tanks, Tetras showcase the true value of sticking close to our friends. Here’s a well-deserved toast to these “Tetrarrific” Fish.
