Max Size: 15cm

Red Tail Hemiodus Tetra (Hemiodus gracilis)

Although the Red Tail Hemiodus Tetras are known as being Semi-Aggressive, this is not the case. People presumably think this is due to their nervous nature, often intimidating smaller, more slow-moving species because of their large size and because they are fast swimmers.

These fish are a relatively peaceful, skittish, shoaling fish that can be quite timid. When put in a single species aquarium, they are best kept in groups of at least ten or more individuals, and should only be kept in well-established aquariums.

In the community tank, they can be kept in a more extensive Amazon biotope set up in small groups with peaceful, similarly-sized fish. They also go well with rainbowfish, Discus, Bala Sharks and Angelfish. It would be best if you did not house them with much smaller species.

Because these Tetras require pristine water quality compared to other fish and are sensitive to poor water conditions, they are not recommended for beginner aquarists. You will be required to do regular partial water changes, and you will need a large tank as these fish do not do well in small aquariums.

Red Tail Hemiodus Tetras have a strong body with a slightly flattened side and a deeply forked tail. Their body colour is silvery with greenish tones, and they have a black band running along the lower edge of their caudal fin. Below the black bar on the lower edge of the caudal fin, there is an intense red stripe.


Red Tail Hemiodus Tetra
Red Tail Hemiodus Tetra
Red Tail Hemiodus Tetra
Quick Facts
Scientific NameHemiodus gracilis
Year Described1864
Other NamesSlender Hemiodus, Red Hemiodus Tetra
OriginsBrazil, Guyana, Venezuela
Aquarium LevelMiddle - Top
Best kept asGroups 10+
Lifespanup to 8 years
Water Parameters
Water TypeFreshwater
PH5.5 - 7.5
GH4 - 15
72 - 80℉
22.2 - 26.7℃


In the home aquarium, the Red Tail Hemiodus Tetra will readily accept most good quality dried foods such as granules, flakes and sinking pellets. These modern food products have been developed to provide all adequate nutrition to maintain your fish's health and dietary requirements.

Providing additional foodstuffs such as live, frozen, and freeze-dried meals such as bloodworm, daphnia, and tubifex once or twice a week will provide additional benefits to your fish's health and well-being but is not a must for this fish.

It should be noted that bloodworms should only be given as an occasional treat and should not be used as the staple diet as they are difficult for fish to digest and can potentially cause blockages.

This fish is an omnivore in the wild, meaning it will consume some vegetable matter. Although most modern fish foods take this into account and include them in their products, you can still supplement your fish's diet with blanched vegetables such as spinach, broccoli, and zucchini. Ensure you do not overfeed your fish and remove any leftovers the following day.

Sexual Dimorphism

Unfortunately, it is practically impossible to sex the Red Tail Hemiodus Tetra. It is believed that mature females are likely to be more rounder-bellied than males.

Other Tetras of interest

Adonis Tetra(Lepidarchus adonis)
African Moon Tetra(Bathyaethiops caudomaculatus)
African Red Eyed Tetra(Arnoldichthys spilopterus)
Arowana Tetra(Gnathocharax steindachneri)
Black Darter Tetra(Poecilocharax weitzmani)
Black Line Tetra(Hyphessobrycon scholzei)
View all Tetras
Date Added: 09/11/2020 - Updated: 12/10/2022 13:01:47