Care Guide For Pencilfish – Surface-Dwelling Schooling Fish

Care Guide for Pencilfish – Surface-Dwelling Schooling Fish The pencilfish is such an interesting surface dweller that everyone should keep at least once. The pencilfish is a hardy, active fish that has pointed snouts and …

Care Guide for Pencilfish – Surface-Dwelling Schooling Fish

The pencilfish is such an interesting surface dweller that everyone should keep at least once. The pencilfish is a hardy, active fish that has pointed snouts and slim, pencil-like bodies. This is their common name. Plus, they exhibit unique behaviors that differ from your typical schooling fish. If you’re interested in getting an unusual nano fish for your next community tank, learn about the wonderful world of pencilfish.

What is a Pencilfish?

These distant relatives of the tetra family are from the Nannostomus genus and can be found in multiple countries all over South America. Many species are available in the aquarium hobby, such as:

– Hockeystick, diptail, or brown pencilfish (N. eques) – Beckford’s pencilfish (N. beckfordi) – golden and red versions – Coral red or red arc pencilfish (N. mortenthaleri) – Purple pencilfish (N. rubrocaudatus) – Dwarf pencilfish (N. marginatus) – One-lined pencilfish (N. unifasciatus) – Three-lined pencilfish (N. trifasciatus)

Although most pencilfish swim horizontally, some pencilfish, such as the diptail pencilfish can swim diagonally at 45 degrees. At least six pencilfish should be purchased from the same species, as they are schooling fish. To lessen aggression, coral red and purple pencilfish can be aggressive towards one another. We recommend that you buy at least 8-10 with a ratio of 1 male to 2 females. Be prepared to save up if you plan on getting a larger school because prices can range from $3-25, depending on the species.

Nannostomus eques – Hockeystick or brown penguinfish


How to Set Up an Aquarium for Pencilfish

Pencil fish can fit in a 10-gallon aquarium, but we personally like a 20-gallon high or 29-gallon tank for them. These taller aquariums are great for displaying fish that swim at different layers, so you can get top-dwelling pencilfish, midwater fish, and bottom dwellers. The coral red and Beckford’s pencilfish are more likely to be found in midwater, so make sure you plan accordingly. Most pencilfish sold at fish stores are wild-caught and prefer tropical temperatures from 75-80degF (24-27degC) and pH from 6.5-7.5. If you need to soften the pH of your water, adding catappa leaves may be a good option.

While pencilfish are not notorious escapers like killifish, they may jump if startled, so make sure to get a tight-fitting aquarium lid. To minimize territorial disputes, ornery species like coral red and purple penguins require lots of plants and tall decorations.

Coral Red Pencilfish (Nannostomus Mortenthaleri).

What fish can live with pencilfish? Pencilfish do well with similar-sized, peaceful fish in a community aquarium. Corydoras and tetras are common tank mates. Also, they are good dither fish that can help shyer species feel more comfortable and hide less, so hobbyists like to pair them with dwarf cichlids like apistogrammas. While some people have successfully kept them with betta fish, be prepared to separate them if the betta is too aggressive. Because pencilfish have been known to predate upon crystal and cherry shrimp, they are not recommended.

What do Pencilfish Eat?

Providing lots of high-quality foods is the key to keeping your pencilfish healthy. Their small, pointed mouths make it difficult for them to eat small foods that sink quickly or float. Avoid fast flowing near the water’s surface to keep the food buoyant. Baby brine shrimps, cyclops and daphnia are our favorite foods to feed.

Three-lined pencilfish (Nannostomus trifasciatus)

How to Breed Pencilfish

It is not always easy to breed all species, but hobbyists have been able to successfully breed Beckford’s pencilfish. You will need a 10-gallon aquarium with a soft pH, warmer temperature at 80degF (27degC), a sponge filter and dim lighting. Next, get a group of at least six to ensure you have at least one male and one female. The parents love to eat their own eggs, so add tons of java moss, dense foliage, spawning mops, and/or a marble substrate to hide the eggs. After feeding them, you will begin to see spawning behavior. The male pokes the female in the stomach to encourage her egg release. At this point, you can either move the eggs to a specimen container with an air stone or remove the parents from the breeding tank.

Depending on the water temperature, eggs can hatch quickly in 1-2 days and the fry become free-swimming in 4-6 days after the yolk sac is absorbed. Feed them powdered fry food, green water, infusoria, vinegar eels, micro worms, and newly hatched baby brine shrimp. It is important to maintain a high water quality. Therefore, you should make daily water changes using low pH water.

Male & female Beckford’s pencilfish (Nannostomus beckfordi red’)

Pencilfish can be kept easily, are good in community tanks and look great against a background of aquatic plant. We hope you enjoy them as much we do. For more options to occupy the top half of your aquarium, check out our article on the 10 Best Top-Dwelling Fish for Your Aquarium.