Not furry, but we like them anyway.
Dwarf Pencilfish
Nannostomus marginatus
Also called Marginal pencilfish
From South America east of the Andes: Guyana, Suriname, Venezuela, Colombia, Peru, Ecuador and Brazil, including the Essequibo, Rio Negro, Napo and Ucayali systems12
A friendly guide, not veterinary advice. For anything about your pet's health, ask your vet.
At a glance the quick version
Looks how to spot one
Short, stocky scaled characin
One of the smallest pencilfish, with a shorter, chunkier body than its relatives, rather like a pencil stub. It wears three dark lengthwise stripes with a red stripe or patch whose length depends on where the fish comes from, plus a red spot at the base of the tail. Males are slimmer than females.13
Personality what they are like
A gentle and somewhat shy fish that fits best with other small, calm species. It also works well as a dither fish that encourages dwarf cichlids to come out.1
Daily activity how busy a day looks
Moves calmly among plants in the middle and lower water levels.12
Grooming and care the hands-on bits
Prefers soft, acidic water. Suggested ranges: about 22-28 C (FishBase gives 24-26 C), pH 4.0-7.0 (FishBase gives 5.8-7.5), hardness 1-10 dGH. Keep conditions clean and stable.12
Home where they are happiest
Tank of at least 45-60 cm length (about 41 litres) with dense planting, leaf litter, soft lighting and very gentle flow.12
Food basics what goes in the bowl
Feeds on tiny invertebrates. Small dried foods are taken, but daily small live or frozen foods such as brine shrimp nauplii, moina and grindal worms are recommended.1
Company who they like around
A sociable fish best kept in a group of 10 or more (FishBase gives 5 as a minimum).12
The story where it all began
Described by Carl Eigenmann in 1909, this species has several regional colour forms. A form once named as a separate subspecies has since been merged into it, and the coral red pencilfish from Peru was first described as one of its subspecies.124
Fun facts for the dinner table
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed September 2020)2
- FishBase
- Described by Eigenmann in 19092
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Dwarf Pencilfish. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
Owner questions the things everyone asks
How often should I feed my Dwarf Pencilfish?
Feed your Dwarf Pencilfish small amounts once or twice a day. Furry Diary's starting plan is to feed daily, offering only what they can eat in a few minutes.1 Furry Diary plan
What does a Dwarf Pencilfish eat, and what should it never eat?
They eat tiny invertebrates and will take small dried foods, but daily live or frozen foods like brine shrimp nauplii, moina, and grindal worms are best. Never feed large or hard foods that could harm their small mouths.1
How much space does a Dwarf Pencilfish need?
A tank of at least 45-60 cm length (about 41 litres) is recommended. This gives them room to swim calmly among plants.12
What temperature, light or water does a Dwarf Pencilfish need?
They prefer soft, acidic water with a temperature of 22-28°C, pH 4.0-7.0, and hardness 1-10 dGH. Soft lighting and very gentle water flow are also important.12
How often should I clean a Dwarf Pencilfish's home?
Furry Diary's plan suggests a weekly 25% water change, weekly glass cleaning, and a monthly filter rinse in old tank water. Keep conditions clean and stable. Furry Diary plan
Can a Dwarf Pencilfish live with others?
Yes, they are sociable and best kept in a group of 10 or more with other small, calm fish. They also work well as dither fish for dwarf cichlids.12
How long does a Dwarf Pencilfish live?
Lifespan varies depending on care and environment. For specific details, ask a good breeder or an exotic-pet vet.
Can I handle a Dwarf Pencilfish?
It's best not to handle them, as they are delicate and shy. They prefer to swim calmly among plants and can be stressed by handling.12
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Furry Diary's own starting care plan. A friendly guide, not a vet's advice.
You might also like
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Golden Pencilfish
Three-lined PencilfishLike what we are building? Buy Archy a bone.
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at support@furrydiary.app and we will fix it.
- Nannostomus marginatus - Seriously Fish seriouslyfish.comused for origin, size, care, diet, behaviour, colour forms
- Nannostomus marginatus summary - FishBase fishbase.seused for size, water parameters, IUCN, etymology
- Nannostomus - Wikipedia en.wikipedia.orgused for body shape, genus lifespan
- seriouslyfish.com seriouslyfish.com
- VCA Animal Hospitals: Feeding times and frequency for your dog vcahospitals.comused for owner questions
- ASPCA: Dog grooming tips aspca.orgused for owner questions
- ASPCA: Cat grooming tips aspca.orgused for owner questions
- ASPCA: People foods to avoid feeding your pets aspca.orgused for owner questions
- RSPCA: What to feed your rabbit rspca.org.ukused for owner questions
Checked 2026-09-30. Text is written in our own words from these sources.