One Single Fish for 30-Gallon Tank

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When it comes to fishkeeping, you will rarely find 2 aquarists with the same preferences and visions.

They have different likes and dislikes in terms of the fish species to get, the plants, the overall layout, the substrate, tank type, size, etc.

Today, we will discuss 1-fish 30-gallon tanks and why they’re more popular than you might suspect.

If you don’t like crowded communities or single-species tanks, today’s article is for you.

10 Best Fish to Keep Alone in a 30-Gallon Tank

There’s no denying that single fish tanks are easier to keep while being at least as thrilling as community tanks.

But there’s another aspect to it that’s worth mentioning: the relationship between you and your fish.

Having one fish to care for will allow you to bond with it better than you could ever bond with a group of fish.

With this in mind, let’s check the 10 best fish species to house solo in your 30-gallon tank:

1. Betta Fish

Bettas won’t grow more than 3 inches, but they showcase a unique beauty and an impressive range of patterns and colors.

These freshwater fish are rather feisty and territorial, especially towards each other. So, they won’t mind living alone, so long as you aquascape their habitat properly.

The ideal environmental stats include:

  • Temperature between 75 and 80 °F
  • PH between 6.8 and 7.0
  • An omnivorous diet, but with a lot more animal than plant-based nutrients

Special Mentions

Bettas are considered labyrinth fish, so expect them to go to the water’s surface frequently. That’s because they use their labyrinth organ for breathing atmospheric air in case the oxygen levels are lower than they should be.

So, don’t have too many floating plants around that could prevent your betta from performing its regular surface breathing.

Also, don’t feed bettas flakes or plant-based foods in excess. Many aquarists rank bettas as carnivorous fish, so their diet should consist of animal protein for the most part.

Finally, keep your betta’s ecosystem clean and well-maintained, despite the fish’s high adaptability and resilience to poor water conditions.

After all, you want your fish to thrive, not just survive. Well-cared-for bettas can reach lifespans of 8-10 years in some cases.

2. Fancy Goldfish

Few fish are cuter, more impressive, and more resilient than fancy goldfish. This Cyprinidae can reach 6 inches in ideal conditions and requires at least 20 gallons of space.

Your 30-gallon setup is even better, given that the typical fancy goldfish will outgrow its 20-gallon home within 5-6 years anyway.

This is a cold-water fish, so aim for temperatures around 50-70 F. This species showcases an astounding diversity, as many goldfish types have been selectively bred for specific physical characteristics.

Choose your goldfish carefully because some species have shorter lifespans than others.

Special Mentions

All goldfish species are messy in general, so your goldfish may require more intensive cleaning and tank maintenance than other species.

This shouldn’t be a problem, given that you’ll have more than sufficient aquarium space for that. Larger tanks are generally easier to clean than smaller ones.

On another note, keep in mind that goldfish are notoriously greedy when it comes to eating. They are the easiest fish to overfeed because of it, as it’s generally not clear when they’re asking for food because they’re hungry or simply greedy.

Always manage your goldfish’s meal size and frequency carefully to prevent digestive problems over time.

As a plus, fancy goldfish don’t need a heater since they’ll do just fine at room temperature.

3. Angelfish

The angelfish ranks as the most popular and beloved cichlid you can get. This is due to the fish’s appearance, behavior, and awesome color and pattern variety.

Angelfish are wider than they are long, capable of reaching 8-10 inches in size.

The ideal water conditions for them include:

  • Temperature between 78 and 85 °F
  • PH between 6.8 and 7.8
  • Water alkalinity between 3 and 8 dKH

These fish are generally peaceful but can get snappy when spawning or when in the presence of other angelfish.

Fortunately, your angelfish won’t have to deal with any tankmates.

Special Mentions

These fish are notoriously sensitive to poor water conditions. You need to have a good maintenance system in place, comprising of weekly partial water changes.

Aim for a weekly 10-25% water change, depending on the situation. A good filtration system is also necessary to keep the angelfish’s habitat clean and well-oxygenated.

Angelfish need more vertical swimming space and a lot of plants and driftwood as decorations.

They are omnivorous fish, so they’re not difficult to feed, but they are somewhat tricky to maintain. I only recommend this species to reasonably experienced aquarists-only.

4. Firemouth Cichlid

Firemouth cichlids are amazing in solo tanks, especially since they are beginner-friendly.

The typical firemouth cichlid can reach 7 inches in captivity and demand at least 30 gallons as an optimal setup.

This cichlid is easily recognizable thanks to its red-splashed abdomen and mouth, imbuing the fish with a ravenous look.

As with any cichlids, this species also prefers warmer waters with temperatures around 75-85 F and a pH of 6.5-8.0.

Keep the water hardness between 8 and 15 dGH and ensure moderate water currents to mimic the cichlid’s natural habitat.

Special Mentions

This is a feisty cichlid which is to be expected from this species. Its semi-aggressive behavior shouldn’t be a problem, though, considering the cichlid will live solo.

The cichlid’s burying behavior could be, though. This species needs a fine, sandy substrate as it likes to bury in it occasionally.

This means that your firemouth cichlid can become a hazard to rooted plants. You should either go for floating plants or secure your plants’ roots with rocks and other decorations that would keep the cichlid away.

Plenty of plants, caves, and pristine water conditions are necessary to preserve your cichlid’s quality of life and boost its lifespan.

Firemouth cichlids can live up to 15 years or more in ideal conditions.

5. Blood Parrot Cichlid

The blood parrot is a hybrid, which is the exclusive result of selective breeding; you can’t find it in the wild.

This cichlid can reach up to 10 inches and requires at least 30 gallons as the ideal setup. The best temperature range sits between 76 and 80 F with a pH level of 6.5-7.5.

This species is great for solo tanks, given that blood parrots aren’t fond of company.

They require a varied ecosystem that includes plants and rocky structures for hiding and exploration.

Special Mentions

Selective breeding isn’t an exact science, and this shows in the blood parrot’s appearance and physiology.

The fish’s mouth is always in a V shape due to genetic faults, and the fish is predisposed to weight issues, making it difficult to swim properly.

Male blood parrots are also infertile, and both males and females show a native predisposition towards spine and bladder problems.

This means that you should never release a blood parrot into the wild.

That’s because, while males can’t reproduce, females can by mating with other types of cichlids. And you don’t want a genetically faulty fish to spread its genes in the wild.

Other than that, this species is reasonably easy to care for.

6. Black Ghost Knifefish

The black ghost knifefish is probably the best solo fish you can get. This ghostly species has a haunting appearance with its long and black body and merged fins.

This semi-aggressive carnivore can reach 20 inches in size and demands at least 100 gallons of space when fully mature.

You can, however, house your knifefish in a 30-gallon setup for a while until the fish indicates that it could use a bit more space.

Aim for temperatures around 73-82 F and a pH range of 6.0-8.0.

Special Mentions

The Black Ghost knifefish is shy and likes to stick to its safe rocky structures near the substrate.

Make sure your knifefish has many dark safe spots to fall back on whenever necessary. Also, go for sand as a substrate to protect the fish’s scaleless skin.

It’s also worth noting that these fish are prone to skin issues due to bacterial and parasitic infections.

Having a UV sterilizer ready is great for keeping the water clean and healthy for your knifefish.

7. Yellow Lab Cichlid

Yellow lab cichlids are gorgeous African cichlids that won’t grow past 4 inches. The pure yellow lab is completely yellow, with a black stripe traversing the upper portion of the dorsal fin.

The cichlid also has dark areas around the eye, as if it were wearing makeup.

This cichlid can live up to 10 years in captivity and requires tropical temperatures around 72 and 82 °F.

But it’s the fish’s behavior and versatility that make it so popular in the aquarium trade. Yellow labs are generally peaceful, easy-going, and easy to accommodate, no matter the tank’s layout.

Special Mentions

The Yellow lab may do fine with a 30-gallon setup for a while, but you should consider upgrading the tank to a 40-50-gallon piece over the years.

Even if the cichlid isn’t that big, it is energetic and likes to explore its habitat constantly. The more space it has, the happier it will be.

But the most important point relates to water quality. This cichlid demands at least 2 partial water changes weekly and constant tank maintenance to remain healthy over the years.

Yellow labs are known to be extremely sensitive to poor water conditions.

8. Paradise Fish

The paradise fish is a 4-inch gourami with long and pointy fins and a striped body. Most specimens come with blue bodies and orange vertical stripes for a colorful and unique appearance.

The long tail is also fully orange for a plus of personality and presence.

This fish ranks semi-aggressive, so it’s not a great addition to a community tank.

The minimum space requirement is 20 gallons, which means that a 30-gallon aquarium will be perfect for it.

Aim for a temperature range of 61-79 °F and a pH range of 5.8-8.0.

Special Mentions

Paradise fish rank among the most adaptable fish species you can get, especially in terms of temperature fluctuations.

Provide your paradise fish with plenty of plants and a variety of places to explore. This will keep the fish mentally active and energetic throughout the day.

9. Kribensis Cichlid

Kribensis cichlids only grow up to 4 inches and can live approximately 5 years in the ideal conditions.

Your typical Kribensis cichlid is brown, grey, or silvery with a red abdomen. This is a peaceful bottom dweller that doesn’t mind living alone.

The perfect temperature for Kribensis cichlids rests between 75 and 77 F with a pH preferably around 6.5-7.0.

Fortunately, Kribensis cichlids exhibit a variety of colors, depending on the type.

Special Mentions

Go for a sand substrate, plenty of plants, and at least a couple of caves that your cichlid can use as hiding.

You can also add a mix of sand and gravel to keep your cichlids busy. This species likes to rearrange its layout as part of its routine activity.

10. Keyhole Cichlid

The Keyhole cichlid has 2 things going for it: its peaceful demeanor and its distinct looks. This 4-5-inch cichlid comes with a yellow-creamy tint and at least 2 distinct black markings.

One of them is located on the upper back flank and resembles a black keyhole; in some species, it may only appear as a spot. The other is the black, thick stripe crossing over the fish’s face and eyes.

This species is peaceful and docile and doesn’t require much to thrive. Aim for calm waters with plenty of vegetation and several hiding spots near the substrate.

The perfect temperature range sits between 68 and 82 °F with a pH of 5.5-7.5.

Special Mentions

Look to preserve the ecosystem’s balance; frequent fluctuations in water parameters can affect the cichlid’s immune system.

Adjust the filter’s output power to keep the water calm with minimal currents.

Also, get a tank with more horizontal than vertical space and cover it with a lid; these cichlids are known jumpers.


Most of these fish will do just fine in a 30-gallon setup, but others may need an upgrade over the years.

Make sure you understand your fish’s requirements and adapt to them as time passes.

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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