Care Guide For Pencilfish – Surface-Dwelling Schooling Fish


Care Guide for Pencilfish – Surface-Dwelling Schooling Fish

The pencilfish is an intriguing surface dweller and should be kept at least once. They are hardy, active fish with pointed noses and pencil-like bodies. These fish have distinct behaviors and are not like other schooling fish. The amazing world of pencilfish is a great option if you are looking for a nano fish to add to your community tank.

What are Pencilfish?

These distant relatives of tetras are from the Nannostomus Genus. They can be found all across South America. Many species are available in the aquarium hobby, such as:

– Brown, diptail or hockeystick pencilfishes (N. eques). – Beckford’s or yellow pencilfishes (N. beckfordi). – Coral red and red arc pencilfishes (N. mortenthaleri). – Dwarf pencilfishes (N. margaratus). – One-lined pencilfishes (N. unifasciatus). – Three-lined penifishes (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. However, coral red and purple pencil fish can be feisty towards each other, so we recommend buying at least 8-10 (with a ratio of one male to two females) to lessen the aggression. Be prepared to save up if you plan on getting a larger school because prices can range from $3-25, depending on the species.

Hockeystick or brown pencilfish (Nannostomus eques)

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. (Coral red and Beckford’s pencilfish tend to swim midwater though, so plan accordingly.) Most pencilfish that are sold in fish stores are wild-caught. They like tropical temperatures between 75-80degF (24-25degC) with a pH of 6.5 to 7. 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. Plus, the ornery species (e.g., coral red and purple pencilfish) need lots of live plants and tall decorations to block line of sight and minimize territorial disputes.

Coral red pencilfish (Nannostomus mortenthaleri)

What fish can live with pencilfish? Pencilfish do well with similar-sized, peaceful fish in a community aquarium. Common tank mates include corydoras, tetras, and rasboras. 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. Some people keep them with betta fish. However, it is possible to have them separated if they become aggressive. Because pencilfish have been known to predate upon crystal and cherry shrimp, they are not recommended.

What do Pencilfish Eat?

Your pencilfish’s health is dependent on you providing them with high-quality food. Because of their small, upturned mouths, they do best with tiny foods that float or take a long time to sink. To keep food buoyant for longer, avoid fast flow near water surfaces. We love feeding baby brine shrimps, cyclops, daphnias, crushed flaflakes, Easy Fry, and Small Fish Food.

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. To ensure that you have at least one male or one female, gather at least six people. To hide eggs from their parents, add lots of javamoss and dense foliage to the mix. You will soon see the male poking the female’s stomach to encourage her to release her eggs. You can then either transfer the eggs to a container with an airstone or take the parents out of the breeding tank.

Eggs can hatch quickly depending on water temperature. Fry become free-swimming after the yolk sac has been absorbed. You can feed them fresh baby brine shrimp, powdered fry food and green water. 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 are easy to keep, do well in community tanks, and look lovely against a background of aquatic plants, so we hope you will enjoy them as much as 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.