Glass tetra
Moenkhausia oligolepis
Also known as Red-eye glass tetra
FreshwaterFish
Care at a glance
- Temperature
- 75–82°F
- 24–28°C
- pH
- 5.5–7.2
- Adult size
- 2 in
- 5 cm
- Minimum tank
- 18 gal
- 70 L
- Temperament
- Mostly peaceful
- Social behavior
- Schooling
- Swim level
- Middle
- Diet
- Omnivore
- Difficulty
- Easy
- Breeding
- Egg scatterer · Medium
- Rarity
- Common
- Family
- Characidae
- Origin
- Northern South America (Venezuela, the Guianas, Amazon basin)
Overview
The glass tetra is an active, mostly peaceful schooling tetra for a roomy community tank. It is easy to keep.
Did you know
The glass tetra's common name comes from its silvery, semi-clear body, but the giveaway feature is the tail. It carries a dark spot at the base of the tail fin, with a bright reflective patch just above it. That marking helps tell it apart from similar silver tetras.
Caring for the glass tetra
Keep at least six glass tetras, and ten or more if you can, in a tank of 18 gal (70 L) or larger. They are active swimmers, so leave open room to move. Stain the water with tannins from driftwood and dried leaves, and add a sand bottom and dim lighting.
Hold the temperature at 75 to 82°F (24 to 28°C), with soft water on the acidic side. A pH of about 6.0 to 7.0, inside the wider 5.5 to 7.2 range, brings out their best color. Feed an omnivore mix of small flakes and pellets, with frozen or live daphnia, bloodworm and brine shrimp to improve color.
Glass tetras are mostly peaceful. In a small group or a cramped tank, though, they can nip fins and pester smaller, slow tank mates. A larger school spreads out that behavior. Skip slow, long-finned tank mates such as bettas and guppies.
They scatter their eggs and give no parental care. Breeding them is a moderate challenge.
Good to know
The glass tetra is a characin in the family Characidae, though FishBase now places it in the revised family Acestrorhamphidae. FishBase lists a wild maximum of around 10 cm, but aquarium adults stay smaller.
In the wild
Glass tetras come from northern South America, across Venezuela, the Guianas and the Amazon basin. There they live in soft, slightly acidic blackwater.
Weekly picks
Tank mates
The glass tetra is a mostly 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)
Pinocchio whiptail
Hemiodontichthys acipenserinus
Freshwater5.3 in (13.5 cm) · 18 gal (70 L)73–82°F (23–28°C)
Blue panchax
Aplocheilus panchax
Freshwater3.5 in (9 cm) · 20 gal (75 L)72–82°F (22–28°C)
Marble wood shrimp
Atya scabra
Freshwater3.9 in (10 cm) · 20 gal (75 L)73–82°F (23–28°C)
Common questions
What size tank does a glass tetra need?
A glass tetra needs at least 18 gal (70 L). It spends most of its time in the middle.
What temperature and pH does a glass tetra need?
A glass tetra is comfortable at 75–82°F (24–28°C) with a pH of 5.5–7.2.
What does a glass tetra eat?
A glass tetra eats an omnivore mix of small flakes and pellets. Frozen or live daphnia, bloodworm and brine shrimp round it out and improve its color.
How big does a glass tetra get?
An adult glass tetra reaches about 2 in (5 cm).
Does a glass tetra need a group?
Yes. A glass tetra is a schooling species and should be kept in a group, not singly.
How does a glass tetra breed?
Glass tetras are egg scatterers that give no parental care. Breeding them is a moderate challenge.
Related species
2.4 in (6 cm)20 gal (75 L)75–82°F (24–28°C)Diamond tetra
Moenkhausia pittieri
2.4 in (6 cm) · 20 gal (75 L)
2.8 in (7 cm)28 gal (105 L)72–79°F (22–26°C)Red eye tetra
Moenkhausia sanctaefilomenae
2.8 in (7 cm) · 28 gal (105 L)
2 in (5 cm)16 gal (60 L)75–82°F (24–28°C)Ceros tetra
Moenkhausia ceros
2 in (5 cm) · 16 gal (60 L)
2 in (5.2 cm)20 gal (75 L)73–82°F (23–28°C)Aurora tetra
Moenkhausia aurora
2 in (5.2 cm) · 20 gal (75 L)
2.1 in (5.3 cm)20 gal (75 L)73–82°F (23–28°C)Blackmargin tetra
Moenkhausia nigromarginata
2.1 in (5.3 cm) · 20 gal (75 L)
1.9 in (4.7 cm)20 gal (75 L)72–81°F (22–27°C)Lopes's tetra
Moenkhausia lopesi
1.9 in (4.7 cm) · 20 gal (75 L)