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Garnet Tetra – Hemigrammus pulcher

Garnet Tetra

Tetras are amongst the most popular aquarium fishes. There are probably more than 150 distinct species of tetra from which the aquarist may choose and this includes a large number of visually stunning fishes that are bound to enhance any home aquarium.

Is the Garnet Tetra a good community fish? The Garnet Tetra could be an excellent community fish and gets on with most species and is most peaceful, bordering on timid. The Garnet Tetra is a rhomboid Tetra in shape. The Garnet Tetra is quite easy to sex because the adult male tends to be both smaller and slimmer than the adult female.

Key Facts

CategoryKey Facts
Common name(s)Garnet Tetra – also known as:
Pretty Tetra
Black Wedge Tetra
Scientific nameHemigrammus pulcher
Originate fromPeruvian Amazon, and probably also in Brazil and Colombia in South America
Care requiredEasy to care for and hugely popular
TemperamentPlacid, shoaling fish
Colour & FormSilver body with garnet arc over eye and garnet patches along spine plus black wedge shape on caudal peduncle
LifespanUp to 2 years
Adult size1.2 inches
DietOmnivorous – eat aquatic insect larvae in nature
Aquarium size24 inches in length or greater
Compatible withMost other Tetras, Barbs, Danios, Guppies and other livebearers, dwarf cichlids, smaller Gouramis, catfish and loaches
Avoid keeping withLarge and/or aggressive species
BreedingEasy if you put the fish in the right environment.
Water temp72 – 82 Fahrenheit
Water pH5.0 to 7.0
Water hardness (dGH or dH)4 to 12 dGH

Origins of the Garnet Tetra

Tetras, as a “family” of fishes belonging to the biological family Characidae are found in nature in Africa, Central America and South America.

The Garnet Tetra is found near Iquitos in the Peruvian Amazon, and probably also in Brazil and Colombia in South America. The vast majority of Garnet Tetras available to aquarists are captive-bred and the species is becoming increasingly popular.

Characteristics of the Garnet Tetra

As you can see, the Garnet Tetra is characterized by its beautifully coloured silver body with a rich garnet coloured arc over the eye, plus a couple of garnet patches, one behind the gill plate, the other between the dorsal and adipose fins along the line of the spine. There is a black patch just between the gill plate and the forward garnet patch and the lower half of the caudal peduncle is also black. The Garnet Tetra will grow to up to 1.2 inches in the aquarium and live for around two years.

Garnet Tetras prefer fairly neutral or acidic water with a pH of 5.0 to 7.0 with a temperature range between 72 and 82 degrees Fahrenheit and up to 4 to12 dGH.

It is generally recommended that Garnet Tetras are kept in peat-filtered aquariums and either as a single species or with companions of a similar size.

In order to maintain the softness and acidity of the water, it is recommended that the aquarium is filtered using aquatic peat. In addition, floating and naturally decomposing Indian Almond leaves are highly recommended. The floating leaves provide the shaded area that the Garnet Tetra will dwell beneath and the decomposing vegetation provides the tannins that will effectively synthesize the “blackwater” conditions found in the natural habitat of the Garnet Tetra.

The Garnet Tetra is a shoaling fish and should be kept as a group of at least six fish, though a shoal of, say, ten or more fish is highly recommended. Having plenty of vegetation to break up lines of sight will also help to protect your Garnet Tetras from predation but it is obviously advised that Garnet Tetras are not kept with predatory species as they are very timid.

It is fairly easy to distinguish between the sexes of the adult Garnet Tetras, as the male tends to be both smaller and slimmer (in profile) than the adult female and, when ready to breed, its colouring becomes much more intense. When the female is carrying eggs (gravid), as her lower abdomen will become more distended than the male. 

The Garnet Tetra has a deeper body than most Tetras that are similar to the Neon Tetra, being much more rhomboid in shape. 

The Garnet Tetra tends to inhabit the middle area of the aquarium. You should also ensure that there is a close-fitting top on the aquarium because the Garnet Tetra will otherwise probably jump out, as jumping clear of the water is in its nature.

The Garnet Tetra is, by nature, a shoaling fish and it is generally recommended to purchase six or more fish, as their nature is to swim together as a shoal and they will tend to thrive much better as a shoal. Garnet Tetras are excellent community fish and are ideal for aquarists with moderate experience, as they don’t tend to have aggressive tendencies towards other species. It is advised not to include Garnet Tetras in an aquarium containing large species, as they may consider them to be food. Garnet Tetras enjoy are plenty of densely clustered plants behind and amongst which they may hide.

Garnet Tetras, like most rainforest species, prefer a shaded and well-planted tank, as they can hide from predation, so consider including floating leaves and/or allowing vegetation to grow so that it floats on the surface of the water to provide shade. Bearing in mind the lower pH levels preferred by Garnet Tetras, they should be kept is an aquatic peat-filtered aquarium

It is generally advised that the minimum tank size for Garnet Tetras should be one of 24 inches in length or more due to the shoaling nature of the species, which will enable a small (or even quite a large) shoal to move around freely. The tank should be well-planted but with clear areas where the fish can swim freely. The water should only have gentle movement.

The general rule for Tetras is that by keeping six or more of the same species in an aquarium they will be fully aware of which is male and which is female and they will act accordingly when the time comes for breeding.

Most (but not all) Tetras have an additional fin which identifies them as being Tetras and the Garnet Tetra is no exception. If you look between the dorsal fin and the caudal (tail) fin of the Garnet Tetra you will observe a tiny, additional fin, known as the adipose fin. The purpose of this fin is not fully understood but, if it is present on a freshwater tropical fish then you can be pretty certain that the fish is a Tetra.

Tetra comes from the Greek word “Tetragonopterus” which means square-finned and appears to relate to the four fins on vertical plane of the fish (dorsal, adipose, caudal and anal fins) which span the central line of the fish (when viewed from above or below, front or rear) and are not present as a pair (e.g. the pectoral or pelvic fins).

Garnet Tetra – Video

How do Garnet Tetras breed?

Here’s the thing about breeding Garnet Tetras…

Tetras eat their eggs and because Garnet Tetras are no exception. A female will lay up to 200 eggs which, if laid in a community tank or a tank with a shoal of Garnet Tetras in, those eggs are unlikely ever to hatch but highly likely to be eaten.

With all of the above noted then the following may be helpful for those considering breeding this pretty specimen.

Tetras, in general, will scatter eggs by laying them over fine plants such as Cabomba, Fontanalis or Java Moss.

Garnet Tetras, like most species, are noted to leap above the water surface during breeding and in general, so it is advised that the tank should be covered to mitigate the risk of losing fish.

As the female Garnet Tetra becomes ripe with eggs, the difference between the sexes becomes even more evident. If you plan to attempt to breed Garnet Tetras then it is recommended that you have a breeding tank prepared. Such a tank can be empty but you may wish to include a mesh or grid under which the fertilized eggs will fall and/or a sterilized breeding mop.

That said, Garnet Tetras will breed in a community tank and, if the tank is well planted, it is possible that at least a few fry may survive to reach adulthood.

Some say that a novice may find it difficult to breed Garnet Tetras but, in my experience, by understanding the conditions that are ideal for breeding, most species will breed quite readily, as it is natural for them so to do and, in general, nature finds a way.

I have observed Garnet Tetras breeding readily and vigorously in quite soft, acidic water (pH 5.5 to 6.0) and less than 12 dGH.

The female will swim vigorously around the tank and, if you include two males then they will encourage her to lay her eggs by bumping into her (though with this species, just a mature male and female is advised. She will lay her eggs which will immediately be fertilized by the male(s) and will fall to the bottom of the tank (preferably through the mesh or trap). Once spawning is complete, remove the adults, as they are likely to consume the eggs, given the chance, and take no further parental responsibility. A mature female may lay in the order of 200 eggs.

Spawning usually takes place in the early morning and is triggered by the rising of the sun.

Breeding tank for Garnet Tetras

You should prepare a tank of around 10 gallons in size with mature water. The water should be at a pH of around 5.0 to 6.0, maintained using an aquatic peat filter and with a low level of light.

You may wish to introduce baby brine shrimp, mosquito larvae or bloodworm as an inducement to reproduction.

The female will swim amongst the plants, laying her eggs whilst the male will swim alongside or behind her and fertilize the eggs as they are laid. Typically, the female can lay up to 200 eggs during a spawning, which may adhere to plants or will sink to the bottom of the tank.

Once the female has scattered her eggs and the male has fertilized at least some of them then the adults should be removed carefully from the breeding tank because they will have nothing more to do with the eggs but they may simply eat them.

Keep the lights off and the tank dark because Tetra eggs and fry are particularly sensitive to the light.

The eggs will hatch typically in around twenty-four hours or so depending on tank temperature and conditions and the fry will become free-swimming after a further two to three days after hatching. Keep the tank unlit for the first week or so then gradually increase the lighting.

The newly hatched fry will firstly feed on their yolk sac but, once free-swimming, can be fed infusoria (particularly rotifers) and will also thrive on egg yolk during the first two to four weeks. It is worth mentioning that immediately after hatching, fry seem quite vigorous but will soon go into a resting state before they become free-swimming so please don’t mistake this initial stage as being free-swimming.

After around four days or so add baby brine shrimp. Once the fry are sufficient in size not to be treated as a snack then they can be introduced into the community tank where they will join the existing shoal. Before moving the adolescent fish into the community tank ensure that you have balanced the water temperatures to mitigate the risk of White Spot or other diseases being triggered.

Should your Garnet Tetras have a special diet for breeding?

Adult Garnet Tetras don’t need any particular inducement to breed. That said, it has been suggested that adding baby brine shrimp and mosquito larva may encourage them, presumably because the addition of a new food may “fool” the fish into thinking that it is breeding time. From my own experience, I would always recommend keeping all of your fish in the best possible condition at all times, as this is good for the wellbeing of your fish.

Image courtesy of Wikipedia Creative Commons

Mike Wheeler

I started keeping freshwater tropical fish in 1972 and it has been something of a passion ever since. In this website, my aim is to build up an everyman's guide to help the everyday aquarist get the best from this inspiring and entertaining hobby.

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