Chalk Basslet Size: The Smallest Reef Fish?


Chalk Basslet Size: The Smallest Reef Fish?

Ever been on a search in the world of reef builders and stumbled upon the term “micro reef ready tank”? Well, that’s where the chalk bass, with its vibrant colors marked by electric blue vertical bands, comes into play

Let's dive into the shimmering waters of coral reefs and unravel this enigma and let's take a look at the smallest reef fish and how to care for these nano reef aquarium fish, shall we?

Chalk Basslet: A Tiny Marvel

Hailing from the tropical waters of the western Atlantic, the chalk bass is not just any fish. With its dominant fish status and electric blue vertical bands decorating its body, it often steals the show in coral reefs.

Believe it or not, the Chalk Basslet is a true bass; its family includes the Giant Grouper and other fish far too huge for your tank, and they might occasionally jump out as the perfect combination of elegance and energy, making it a great fish for schooling.

These little bass doesn't grow larger than 3 inches.

The chalk basslet is a peaceful saltwater fish and ideal for smaller reef setups. Chalk basslets also live together in harmony.

  • Scientific Name: Serranus tortugarum
  • Origin: Caribbean Sea
  • Length: 3 inches
  • Tank Size: 20 gallons

NOTE: Chalk basslets are also predatory fish. But they only eat small fish fry and shrimp.

What's the Smallest Reef Tank?

When we speak of the “smallest reef tank”, the micro reef ready tank stands out. This setup provides the perfect setting for our chalk bass and other species to flourish.

Are Nano Reef Tanks Hard to Keep?

A nano reef tank is not a saltwater aquarium for absolute beginners. In fact, they are more challenging than larger saltwater tanks. Nano aquarium (and pico reef tank) setups can shift in parameters faster than a larger fish tank.

Such a small aquarium will respond fast if leftover food or a dead fish decays into ammonia. A power outage will cause the water to cool faster. Evaporation will increase salinity faster. And so on.

You need to be very good at maintaining reef fish and coral water conditions. These animals thrive with stability. Remember, the conditions of the ocean hardly change over even thousands of years.

Also, there are not as many fish for nano reef aquarium setups. Most popular saltwater fish species tend to be medium-sized fish or larger. They need tanks larger than 30 gallons in volume.

What if you don't want larger reef fish and want to try smaller saltwater aquariums? Think about trying some of these reef-safe fish sized for nano tanks:

Fluval Evo V Marine Aquarium Kit


Suited for those who prioritize location, this is where rock meets sand, and life develops in all its glory.


  • Compact Design: Ideal for hobbyists with limited space or those wanting a smaller display.
  • Integrated Filtration: Comes with a powerful 3-stage filtration system, ensuring clear water and a healthy environment.
  • LED Lighting: The high-output LED promotes coral growth and brings out fish colors vividly.
  • Ease of Set-Up: Designed for simplicity, making it suitable for beginners to intermediates.


  • Size Limitation: Being a small tank, it restricts the number of species and quantity you can introduce.
  • Component Quality: Some users may find certain components, like the pump, might need an upgrade for optimal performance.

Innovative Marine Nuvo Fusion Pro Aquarium


When rock and room unite, this tank emerges as the victor, ideal for the chalk bass and its school to roam.


  • Modern Design: Sleek and contemporary aesthetics make it a centerpiece in any room.
  • Advanced Filtration: Uses a sophisticated filtration system, ensuring the best water quality.
  • Customizable Set-Up: Offers flexibility in configuring the equipment to cater to specific needs.
  • Integrated Skimmer & Media Caddy: Essential tools for maintaining water quality are built-in.


  • Price Point: Typically more expensive than other tanks of a similar size.
  • Requires Knowledge: Due to its advanced features, beginners might find it a bit overwhelming initially.

Why Buy for Chalk Basslet?

Chalk Basslet is a small, peaceful, and hardy fish, making it an ideal resident for nano tanks like the Fluval Evo V and the Innovative Marine Nuvo Fusion Pro. These tanks provide:

  1. Right Size Environment: Chalk Basslet doesn’t require a large space to thrive. These tanks offer a perfect-sized environment for them.
  2. High Water Quality: Both tanks emphasize filtration, which ensures a clean and stable environment. This is key for the health of the Chalk Basslet.
  3. Visual Appeal: Chalk Basslet's vibrant coloration will stand out brilliantly, especially with the LED system of the Fluval Evo V and the clear design of the Nuvo Fusion Pro.

Nano Reef Tank Saltwater Fish: A Look at the Littles

While the chalk bass, with its vibrant colors, stands out, let’s not forget the many other contenders in this underwater school:

Royal Gramma


The Royal gramma is a peaceful and small saltwater fish from the Caribbean Sea. Growing no larger than 3 inches they are an ideal nano reef tank inhabitant.

They are carnivorous, feeding on brine shrimp and other small invertebrates. The diet of these reef dwellers occasionally links back to their easy preferred diet, making them an easy-going addition to any tank.

While a Royal Gramma will spend most of its time out in the open. But they do need caves and other hiding places to retreat to.

Grammas can be aggressive fish if they have to compete with their tank mates for places to hide. So provide plenty of hiding spaces for everyone. They are also aggressive towards their own species. So only keep one gramma per nano tank.

  • Scientific Name: Gramma loreto
  • Origin: Caribbean Sea
  • Length: 3 inches
  • Tank Size: 30 gallons

Six Line Wrasse


Six Line Wrasses are striking fish, with purple and orange horizontal stripes running along their flanks. They may look delicate but these wrasses are hardy fish and long-lived as well: up to 10 years in captivity.

The Six Line Wrasse is reef safe and won't bother corals. But they do eat small invertebrates so keep them away from tiny shrimp and hermit crabs. Larger shrimp (like Coral Banded shrimp) won't be molested, however.

Also, be aware that Six Line Wrasses are not timid fish. They can be aggressive towards other tank mates, nipping at fins and competing for food. Keep them with fish that can defend themselves like Grammas, Pygmy Angelfish, Damselfish, and Tangs.

  • Scientific Name: Pseudocheilinus hexataenia
  • Origin: Indo-Pacific Ocean
  • Length: 3 inches
  • Tank Size: 30 gallons

Neon Goby Fish


Neon gobies are from the Atlantic Ocean, where they perform the same services as the better known cleaner wrasse. These gobies will sit on coral perches and wait for large fish to come by.

They then pick parasites from their skin, gills, and even their teeth. Being such small fish, neon gobies are great additions to a small nano aquarium. They eat prepared foods and frozen foods with equal gusto.

Neon gobies are peaceful fish and will live in the same aquarium with each other. A bonded male/female pair may become a little territorial, however.

  • Scientific Name: Elacatinus oceanops
  • Origin: Atlantic Ocean
  • Length: 1.5 to 2 inches
  • Tank Size: 10 gallons

Ocellaris Clownfish


Also known as the false percula clownfish, the ocellaris clownfish is one of the most popular and interesting fish in the saltwater hobby.

Ocellaris clownfish live in symbiotic relationships with sea anemones. Anemones can be a little challenging to keep. They need excellent water quality and ample lighting of the right spectrum. But you can keep clownfish in community saltwater tanks without one.

Clownfish are poor swimmers when they don't have an anemone to hide in, though. So make sure your water currents are gentle enough for them to get around.

  • Scientific Name: Amphriprion ocellaris
  • Origin: Western Pacific Ocean
  • Length: 3 inches
  • Tank Size: 20 gallons

Coral Beauty Angelfish


The coral beauty angelfish is a species of pygmy angelfish, staying much smaller than most of their larger cousins. Angelfish are grazers, feeding on sponges, algae, and other encrusting organisms.

Coral beauties may pick at some species of corals. So long as they are well fed, however, pygmy angelfish are mostly reef-safe.

The coral beauty angelfish is at the very limit of what we would consider a nano fish. While they will live comfortably in a 30-gallon tank they may become aggressive towards very peaceful fish.

Keep coral beauties with semi-aggressive tank mates unless the tank is more spacious.

  • Scientific Name: Centropyge bispinosa
  • Origin: Indo-Pacific Ocean
  • Length: 3-4 inches
  • Tank Size: 30+ gallons



Is a single fish like the Chalk Bass suitable for all reef tanks?


Especially when there are conch shells and live rock formations for them to play hide and seek.

What are Nano and Pico Reef Tanks?

As you'd expect, nano and pico reefs are aquariums at the smaller end of the reef-keeping spectrum. Nano reef tanks are saltwater aquariums 30 gallons or smaller.

Meanwhile, a pico reef tank is one 5 gallons or less!

How do they coexist with new fish in the same territory?

As schooling fish, they can stand their own, but if they stop eating or display signs of distress, it might be time to reassess the settings.

Why Choose Nano Reef Tanks?

Nano reef fish are usually less expensive than larger reef aquarium fish since they are so small. Yet most of your choices are still vibrant fish, just like other reef animals.

A nano reef tank also costs significantly less to both setup and maintain.

NOTE: Just be aware that there are also downsides to smaller nano reef systems.

What are the other species that can thrive in a micro reef ready tank?

From abandoned shells dwellers to those that dive deep into the sand, there’s a variety of marine life that can make the tank their home.

Want to Read More Articles?

Before we wrap, if you're in for more, don't just stop here! For a deeper dive:

  1. Best Nano Aquariums | Top 4 Pros & Cons
  2. Small Saltwater Fish Tank: The Best Options

And, of course, our lively community awaits on Facebook.

Join Here! (LINK)



The world of coral reefs is vast, with the chalk bass, in its electric blue vertical bands, leading the parade of the smallest reef fishes. Whether you're into diving deep into marine settings or just here for the schooling fun,

REMEMBER: Life in these tanks is as diverse as the rock formations and the stories they tell.

Dive, swim, or simply watch—every choice is an adventure.


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