Slender rasbora
Rasbora daniconius
Also known as Blackline rasbora, Striped rasbora, Slender barb
FreshwaterFish
Care at a glance
- Temperature
- 72–81°F
- 22–27°C
- pH
- 6.0–7.5
- Adult size
- 3.9 in
- 10 cm
- Minimum tank
- 32 gal
- 120 L
- Temperament
- Peaceful
- Social behavior
- Schooling
- Swim level
- Middle
- Difficulty
- Easy
- Breeding
- Medium
- Rarity
- Common
- Family
- Cyprinidae
- Origin
- Widespread across South and Southeast Asia, from Sri Lanka and India to the Mekong basin.
Overview
Keep slender rasboras in a group of at least eight in a tank of 120 litres or more, since they are active swimmers that reach around 10 cm. Water at 22 to 27 C with a pH of 6.0 to 7.5 suits them, and a lid is wise as they can jump. Feed flakes, pellets, and frozen or live foods such as daphnia, bloodworm, and mosquito larvae. They are peaceful and make good dither fish for larger community tanks.
In the wild
The slender rasbora lives across a huge range of streams, rivers, ponds, and ditches from Sri Lanka and India into mainland Southeast Asia. It shoals in open midwater and adapts to many conditions. A bold dark stripe edged with gold runs the length of a slim silver body. It is a hardy, active rasbora that grows larger than the common nano species.
Good to know
Rasbora daniconius has carried many common names, including blackline, striped, and golden striped rasbora, reflecting its wide range and long history in the hobby. It reaches about 10 cm in the tank and more in the wild. Its broad distribution means fish from different regions vary in size and exact color.
Did you know
The gold-edged black stripe catches the light as the shoal moves, and in older books this was one of the standard beginner rasboras before the smaller nano species took over.
Weekly picks
Tank mates
Slender rasbora 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.
Moustached danio
Danio dangila
Freshwater5.1 in (13 cm) · 32 gal (120 L)68–79°F (20–26°C)
Firemouth cichlid
Thorichthys meeki
Freshwater5.9 in (15 cm) · 30 gal (115 L)73–82°F (23–28°C)
Duboulayi's rainbowfish
Melanotaenia duboulayi
Freshwater4.7 in (12 cm) · 30 gal (115 L)64–82°F (18–28°C)
Marbled hatchetfish
Carnegiella strigata
Freshwater1.6 in (4 cm) · 32 gal (120 L)68–82°F (20–28°C)
Bugeye squeaker
Synodontis contractus
Freshwater3.9 in (10 cm) · 30 gal (114 L)72–79°F (22–26°C)
Montezuma swordtail
Xiphophorus montezumae
Freshwater5.5 in (14 cm) · 32 gal (120 L)68–79°F (20–26°C)
Common questions
What size tank does a Slender rasbora need?
A Slender rasbora needs at least 32 gal (120 L). It spends most of its time in the middle.
What temperature and pH does a Slender rasbora need?
A Slender rasbora is comfortable at 72–81°F (22–27°C) with a pH of 6.0–7.5.
How big does a Slender rasbora get?
An adult Slender rasbora reaches about 3.9 in (10 cm).
Does a Slender rasbora need a group?
Yes. A Slender rasbora is a schooling species and should be kept in a group, not singly.
Related species
3.5 in (9 cm)20 gal (75 L)72–82°F (22–28°C)Brilliant rasbora
Rasbora einthovenii
3.5 in (9 cm) · 20 gal (75 L)
3.1 in (8 cm)32 gal (120 L)72–79°F (22–26°C)Sidestripe rasbora
Rasbora paviana
3.1 in (8 cm) · 32 gal (120 L)
5.5 in (14 cm)45 gal (170 L)72–77°F (22–25°C)Scissortail rasbora
Rasbora trilineata
5.5 in (14 cm) · 45 gal (170 L)
3.9 in (10 cm)34 gal (130 L)73–82°F (23–28°C)Clown rasbora
Rasbora kalochroma
3.9 in (10 cm) · 34 gal (130 L)
2.4 in (6 cm)18 gal (70 L)72–79°F (22–26°C)Red-tailed rasbora
Rasbora borapetensis
2.4 in (6 cm) · 18 gal (70 L)
1.8 in (4.5 cm)15 gal (55 L)73–79°F (23–26°C)Volcano rasbora
Rasbora vulcanus
1.8 in (4.5 cm) · 15 gal (55 L)