Dwarf pencilfish
Nannostomus marginatus
FreshwaterFish
Care at a glance
- Temperature
- 72–82°F
- 22–28°C
- pH
- 5.0–7.0
- Adult size
- 1 in
- 2.5 cm
- Minimum tank
- 12 gal
- 45 L
- Temperament
- Peaceful
- Social behavior
- Shoaling
- Swim level
- Middle
- Difficulty
- Medium
- Breeding
- Egg scatterer · Medium
- Rarity
- Rare
- Family
- Lebiasinidae
- Origin
- Peru, Colombia, Brazil
Overview
The dwarf pencilfish is one of the smaller pencilfish, a peaceful shoaling fish for a soft-water planted tank. It is best kept by someone with some experience.
Did you know
Like other pencilfish, dwarf pencilfish switch their coloring at night. The crisp daytime stripe breaks up into a blotchy pattern once the lights go out, then snaps back in the morning.
Caring for the dwarf pencilfish
Keep dwarf pencilfish in a tank of at least 12 gal (45 L), with dim lighting, fine plants, driftwood and dried leaves. Keep the flow gentle. The water should be warm, soft and acidic, at 72 to 82°F (22 to 28°C) and a pH of 5.0 to 7.0.
Their mouths are tiny, so feed small foods like crushed flakes and micro pellets. Baby brine shrimp and daphnia suit them too.
Keep them in a group of at least six. They hold the middle of the water and move in a slow, deliberate way rather than darting. They are peaceful and best matched with other small, calm fish. They are egg scatterers, and breeding them takes some effort.
Good to know
The dwarf pencilfish belongs to the family Lebiasinidae. Its slim body carries a dark horizontal stripe with bordering lines, and its fins show red.
In the wild
Dwarf pencilfish live in slow, heavily planted blackwater across Peru, Colombia and Brazil, in streams and flooded forest with leaf litter underfoot. The water is soft, acidic and dark with tannins.
Weekly picks
Tank mates
The dwarf pencilfish is a peaceful, shoaling 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)
Wandering snail
Ampullaceana balthica
Freshwater0.8 in (2 cm) · 11 gal (40 L)50–84°F (10–29°C)
Reynolds's cory
Hoplisoma reynoldsi
Freshwater1.4 in (3.5 cm) · 12 gal (45 L)72–79°F (22–26°C)
Honey blue-eye
Pseudomugil mellis
Freshwater1.4 in (3.5 cm) · 11 gal (40 L)68–82°F (20–28°C)
Common questions
What size tank does a dwarf pencilfish need?
A dwarf pencilfish needs at least 12 gal (45 L). It spends most of its time in the middle.
What temperature and pH does a dwarf pencilfish need?
A dwarf pencilfish is comfortable at 72–82°F (22–28°C) with a pH of 5.0–7.0.
What does a dwarf pencilfish eat?
A dwarf pencilfish has a tiny mouth, so it eats small foods like crushed flakes and micro pellets. It also takes baby brine shrimp and daphnia.
How big does a dwarf pencilfish get?
An adult dwarf pencilfish reaches about 1 in (2.5 cm).
Does a dwarf pencilfish need a group?
Yes. A dwarf pencilfish is a shoaling species and should be kept in a group, not singly.
How does a dwarf pencilfish breed?
Dwarf pencilfish are egg scatterers. Breeding them takes some effort.
Related species
1.1 in (2.8 cm)11 gal (40 L)75–82°F (24–28°C)Least pencilfish
Nannostomus minimus
1.1 in (2.8 cm) · 11 gal (40 L)
1.2 in (3 cm)15 gal (55 L)72–82°F (22–28°C)Barred pencilfish
Nannostomus espei
1.2 in (3 cm) · 15 gal (55 L)
1.2 in (3 cm)15 gal (55 L)75–82°F (24–28°C)Coral red pencilfish
Nannostomus mortenthaleri
1.2 in (3 cm) · 15 gal (55 L)
0.7 in (1.9 cm)5 gal (20 L)75–82°F (24–28°C)Anduzei pencilfish
Nannostomus anduzei
0.7 in (1.9 cm) · 5 gal (20 L)
1.3 in (3.3 cm)15 gal (55 L)72–82°F (22–28°C)Three-lined pencilfish
Nannostomus trifasciatus
1.3 in (3.3 cm) · 15 gal (55 L)
1.4 in (3.5 cm)15 gal (55 L)72–82°F (22–28°C)Hockeystick pencilfish
Nannostomus eques
1.4 in (3.5 cm) · 15 gal (55 L)