Ruby tetra
Axelrodia riesei
Also known as Riese's tetra, Red ruby tetra
FreshwaterFish
Care at a glance
- Temperature
- 73–81°F
- 23–27°C
- pH
- 5.0–7.0
- Adult size
- 0.8 in
- 2 cm
- Minimum tank
- 12 gal
- 45 L
- Temperament
- Peaceful
- Social behavior
- Schooling
- Swim level
- Middle
- Difficulty
- Medium
- Breeding
- Hard
- Rarity
- Rare
- Family
- Characidae
- Origin
- Endemic to the Rio Meta drainage in the llanos of eastern Colombia.
Overview
The ruby tetra is a tiny red schooling fish for a shaded blackwater tank. It is a step up from the easiest tetras.
Did you know
The ruby tetra's whole body glows a deeper ruby red when the water is soft and acidic.
Caring for the ruby tetra
Keep ruby tetras in a group of at least eight to ten, in 12 gal (45 L) or larger. A lone fish or a tiny group will hide and lose color. A dark substrate, botanicals and leaf litter bring out their red.
Give them soft, tannin-stained water at 73 to 81°F (23 to 27°C) and a pH of 5.0 to 7.0. They are easily outcompeted at feeding time, so pair them only with other tiny, gentle fish.
Ruby tetras are peaceful and swim in the middle of the tank. Breeding them is hard.
Good to know
Axelrodia riesei is one of the smallest characins in the hobby, in the family Characidae. Its warm red body carries a small dark spot at the base of the tail. The genus name honors the tropical fish author Herbert Axelrod.
In the wild
Ruby tetras come from the Rio Meta drainage in the llanos of eastern Colombia. They live in slow, shaded blackwater creeks and forest streams stained brown by tannins. The water is soft, acidic and often shallow, with leaf litter and submerged wood on the bottom. These little tetras hang in loose groups among roots and overhanging plants.
Weekly picks
Tank mates
The ruby tetra is a peaceful, schooling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.
Neocaridina shrimp
Neocaridina davidi
Freshwater1.6 in (4 cm) · 5 gal (19 L)59–84°F (15–29°C)
Guppy
Poecilia reticulata
FreshwaterBrackish2.4 in (6 cm) · 10 gal (38 L)64–82°F (18–28°C)
Neon tetra
Paracheirodon innesi
Freshwater1.5 in (3.8 cm) · 11 gal (40 L)70–77°F (21–25°C)
Chopstick snail
Stenomelania torulosa
Freshwater2 in (5 cm) · 11 gal (40 L)73–82°F (23–28°C)
Bumblebee otocinclus
Rhinotocinclus isabelae
Freshwater0.8 in (2 cm) · 11 gal (40 L)73–82°F (23–28°C)
Borneo gold spot halfbeak
Hemirhamphodon tengah
Freshwater1.8 in (4.5 cm) · 11 gal (40 L)73–81°F (23–27°C)
Common questions
What size tank does a ruby tetra need?
A ruby tetra needs at least 12 gal (45 L). It spends most of its time in the middle.
What temperature and pH does a ruby tetra need?
A ruby tetra is comfortable at 73–81°F (23–27°C) with a pH of 5.0–7.0.
How big does a ruby tetra get?
An adult ruby tetra reaches about 0.8 in (2 cm).
Does a ruby tetra need a group?
Yes. A ruby tetra is a schooling species and should be kept in a group, not singly.
Related species
0.8 in (2 cm)9 gal (35 L)72–82°F (22–28°C)Ember tetra
Hyphessobrycon amandae
0.8 in (2 cm) · 9 gal (35 L)
0.8 in (2 cm)12 gal (45 L)73–81°F (23–27°C)Hummingbird tetra
Trochilocharax ornatus
0.8 in (2 cm) · 12 gal (45 L)
0.8 in (2 cm)12 gal (45 L)75–82°F (24–28°C)Tucano tetra
Tucanoichthys tucano
0.8 in (2 cm) · 12 gal (45 L)
0.8 in (2 cm)7 gal (25 L)68–82°F (20–28°C)Yellow phantom tetra
Hyphessobrycon roseus
0.8 in (2 cm) · 7 gal (25 L)
0.7 in (1.9 cm)5 gal (20 L)73–81°F (23–27°C)Tambopata glass tetra
Tyttocharax tambopatensis
0.7 in (1.9 cm) · 5 gal (20 L)
0.9 in (2.4 cm)11 gal (40 L)68–79°F (20–26°C)Krieg's tetra
Serrapinnus kriegi
0.9 in (2.4 cm) · 11 gal (40 L)