10 Best Pencil Fish Tank Mates

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If you’ve decided to get Pencil fish, I can understand why. This tiny genre consists of several distinct species, each with unique features and patterns. Many fish lovers keep Pencil fish-only tanks since this is a shoaling species; you need to keep the fish in groups of minimum 10 individuals.

It’s also worth noting that some species of Pencil fish don’t fare well in community tanks. They prefer each other’s and will become timid, withdrawn, and even stressed in the presence of other fish, especially more territorial, larger, and aggressive ones. That being said, many Pencil fish can accommodate to community tanks quite well.

It all depends who you’re pairing them with. Today, we will discuss the 10 fish species that are compatible with Pencil fish.

1. Tetras

Neon Tetra

Peaceful, colorful, and diverse. These 3 qualities make tetras some of the most prized aquarium fish you can get.

Behavior – Calm and friendly, displaying schooling behavior. You should keep them in groups of minimum 6 fish, which will provide them with comfort and make them bolder and extroverted. They can cohabitate with fish with similar personalities, the Pencil fish making for a great candidate.

Tank Requirements – Tetras require stable temperatures between 75 and 80 °F and need regular water changes and a reliable filtration system. They need clean and fresh waters to remain healthy in the long run. Regarding the tank’s size, this remains your choice.

The absolute minimum for tetras would be 10 gallons, but I recommend more than that, especially since you’ll pair them with a Pencil fish shoal.

Diet – Omnivorous. Provide them with a varied diet and avoid overfeeding them. Tetras should only eat twice per day at most, and only what they can consume within 2 minutes.

2. Barbs

This is another schooling species, coming with colorful and friendly specimens. Several types of Barbs are available, including tiger Barb, Rosy Barb, Black Ruby Barb, etc.

Each comes in different sizes, colors, and patterns, making for quite an impressive addition to your community tank.

Behavior – Lively, friendly, and inquisitive. Barbs are peaceful fish that enjoy the company of other aquatic creatures, so long as they’re not aggressive. They may be overly energetic and playful, so you might want to monitor their dynamics with the Pencil fish.

They also display schooling behavior, which means you need at least 5 or 6 specimens to build a stable and thriving group.

Tank Requirements – The minimum tank size is 20 gallons for a school of Barbs. Ideally, you should double it, seeing as you also have Pencil fish to account for. The best temperature ranges between 72 to 79 °F in soft acidic waters.

Diet – Omnivorous. Barbs consume animal and plant-sourced nutrients, ideally from varied sources. You can provide them with homemade fish food and commercial options to make sure they’re getting all the nutrients they need.

3. Rasboras

Harlequin Rasboras

Harlequin Rasboras

These tiny fish will only grow up to 1.7 inches, which is what a typical Pencil fish will revolve around. They bring color, numbers, and a vivid personality that will enrich your aquarium from day one.

Behavior – Peaceful and non-combative. Rasboras are shoaling and schooling in nature and will never attack other fish. Their timid nature may turn them into victims if you pair them with larger or aggressive fish. This makes the Pencil fish one of the ideal mates for this species.

Tank Requirements – Since Rasboras are so petite, you should keep them in shoals of 10 individuals minimum, same as the Pencil fish. Provide them with minimum 30 gallons of water to enjoy higher comfort and safety.

However, since you will have around 20 fish in the same habitat, I would recommend larger tanks. The ideal temperature revolves around 73 to 82 °F.

Diet – Omnivorous. You can feed Rasboras and Pencil fish similar diets, making sure you don’t overfeed them in the process.

4. Guppies

Guppy Fish

Guppy Fish

Guppies need no introduction at this point. These colorful, diverse, and vivacious fish are every hobbyist’s go-to species.

It doesn’t matter whether you’re setting a species-only or community tank, you can’t not have guppies in the mix.

Behavior – Friendly and overall peaceful. Guppies are very acceptant of other fish species, making them ideal for community tanks, so long as you don’t pair them with aggressive species.

You should keep guppies in groups of minimum 5 fish and ensure a balanced male-to-female ratio. Every male should have access to at least 2 females to prevent male aggression and overly adventurous territorial behavior.

Tank Requirements – Guppies need stable water temperatures, varying between 72 and 82 °F. You should also provide guppies with at least 2 gallons of water per fish to ensure their comfort long-term. Regular water changes are a must.

Diet – Omnivorous. Guppies aren’t picky eaters. They thrive on life food, frozen pellets, veggies, spirulina, etc. You can either make their food at home, use several ingredients, or purchase it online from fish stores specializing in fish food. I recommend the former since it allows you to personalize their diets easier.

5. Mollies


Molly Fish

Mollies are gorgeous, on pair with guppies in terms of popularity in the aquarium world. They have been bred selectively for generations, resulting in a wild variety of subspecies, each with their own characteristics, coloring, and patterns.

Behavior – Peaceful and acceptant of other fish species. You can pair them with Pencil fish, so long as you provide both species with plenty of room to swim.

Tank Requirements – The temperature should range between 73 to 80 °F but should ideally remain stable in the mid-70s. Other than that, mollies and Pencil fish share similar environmental conditions – clean waters, good oxygenation, plant-rich environments, etc.

Diet – Mollies are omnivorous but will typically enjoy more plant-based diets. Provide them with spirulina flakes, live food, boiled spinach, and veggie paste to keep them healthy. They will also eat some of your tank algae, making them a useful addition to the aquarium.

6. Corydoras

Cory Catfish

Cory Catfish

Corydoras are easy to care for, adaptable, and colorful, making them ideal for community tanks.

Their tiny whiskers and armored bodies will cause them to make quite the visual impact.

Behavior – Corydoras are bottom-dwelling fish, taking pleasure in swimming and feeding near the substrate. They are more timid in nature and will enjoy the company of friendly and easy-going fish species. Pencil fish will make for great tank mates.

Tank Requirements – Maintain the water’s temperature between 72 and 78 °F and provide them with stable water conditions. Monitor the water’s pH, temperature, and ammonia levels constantly.

Corydoras don’t do well in dirty tanks, so keep their environment as clean as possible. Regular water changes, substrate vacuuming, and tank cleaning are musts.

Diet – Corydoras thrive on an omnivorous diet, enjoying everything from pellets, food flakes, and fish tablets to food leftovers from medium-to-top dwellers.

7. Platies


Platy Fish

Platies are some of the most colorful and energetic fish you can find. This species comes with a wide variety of colors and can grow up to 3 inches under optimal conditions.

Behavior – While Platies are neither shoaling nor schooling, they do prefer the company of their own. Keep them in small groups to make sure they remain comfortable and healthy in the long run. Otherwise, they are friendly and peaceful fish and will get along just fine with both Pencil fish and other peaceful aquarium species.

Tank Requirements – Platies prefer water temperatures between 72 and 75 °F with a water hardness of up to 8. While this fish species is hardy and adaptable, it still needs a clean and fresh environment to remain healthy over the years. You should change around 20% of their water weekly or, at a minimum, every other week to keep their habitat stable.

Diet – Omnivorous, but Platies enjoy more vegetables in their diet. Flake foods should make up the majority of their meals, along with cucumber, spinach, spirulina, etc.

8. Swordtails

Swordtail Fish

Swordtail Fish

Swordtails are low maintenance and will provide your tank with a powerful presence. The male’s caudal fin gives the fish personality and its bright coloring and easy-going personality.

Behavior – Friendly and acceptant of other species. Males can get aggressive and territorial at times, a temperament which you can mitigate by providing them female company. Swordtails make for a great addition to community tanks.

Tank Requirements – If you’re planning on pairing Swordtails with Pencil fish, get a large tank. One Swordtail should have at least 15 gallons of water to its name. Seeing as you will ideally have several Swordtails (they fare the best when it the company of their own), along with 10 or more Pencil fish, a tank upgrade is necessary. Water temperature should remain between 75 to 79 °F.

Diet – Omnivorous. The Swordtail’s diet matches that of the Pencil fish.

9. Bristlenose Pleco

Thanks to their usefulness, peaceful behavior, and appearance, the Bristlenose is a staple species for most community tanks.

Their splattered look and tentacle-like whiskers are worth every penny.

Behavior – A peaceful and easy-going creature, as any bottom-dwelling species should be. This makes the Bristlenose Pleco ideal for community tanks, so long as they remain the only bottom-dwelling species in the habitat.

Tank Requirements – One Bristlenose Pleco requires ideally 40 gallons of water and a steady temperature of 73 to 81 °F.

Diet – Herbivorous. The Bristlenose Pleco will spend most of its time near the substrate, looking for plants and algae. You can occasionally feed them spirulina tablets, flakes, algae wafers, and even bloodworms.

Just make sure you don’t overfeed them since they will also eat tank algae whenever they get the chance.

10. Dwarf Gourami

This top-to-mid dweller makes for a fine addition to any community tank. It’s relatively easy to care for, and its distinct look, with the 2 pectoral whiskers, will add a drop of diversity to your tank.

Behavior – Shy and timid, ideal for likewise species like the Pencil fish. The Dwarf Gourami tends to breathe air oxygen occasionally, so make sure they get easy access to the water’s surface. Also, the Dwarf Gourami is a bubble nester. So, don’t get scared if you notice bubble foam at the water’s surface when the breeding time arrives.

Tank Requirements – One Dwarf Gourami needs around 5 gallons of water and temperatures varying between 72 to 82 F. Clean the tank regularly and change their water weekly. But this goes without saying.

Tank Mates to Avoid

Now that you know which tank mates are ideal for your Pencil fish, you must also learn which ones to avoid. The most notable ones include:

– Large Cichlids

These are beasts size-wise, by aquarium standards. Many cichlids can reach in excess of 12 inches, going all the way up to 18 or even 20 inches. They require a lot of water volume, depending on each species’ size and requirements, display aggressive territorial behavior, and will eat smaller fish.

They are typically omnivorous and will appreciate Pencil fish in their environment for all the wrong reasons. Cichlids will hunt and consume smaller fish if given the opportunity, and the Pencil fish fits their menu easily. It’s not a smart idea to pair the two species.

– Male Bettas

Bettas are loners as they’re neither shoaling nor schooling. This means that they don’t do well in groups, and this is twice as true for males. Male Bettas are highly territorial and will display aggressive behavior towards other fish. Pairing them with small species like the Pencil fish is a bad idea since they may become victims of Betta aggression and even food.

After all, they are known as the Siamese fighting fish for a reason.

– Goldfish

Goldfish can reach impressive sizes of up to 16 inches and measure around half a pound in captivity. They are intelligent, adaptable, and require lower water temperatures, between 68 to 74 F. Their impressive size translates to a lot of fish waste and the need for a lot of available space.

Although they are typically peaceful towards other species, that goes out the window when the size difference gets in the way. Goldfish can easily eat Pencil fish due to the size differences between the two.


Pencil fish make for energetic and handsome community fish. Learn about their care requirements and find them compatible tank mates, and they will thrive.

The profile of the ideal tank mate for the Pencil fish should include qualities like the ease of care, peaceful behavior, omnivorous or herbivorous diet, and low territorial tendencies.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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