Pico Reef: The Ultimate Guide

Even if you’re not a newbie to fishkeeping and aquariums, you might not have heard about pico tanks as they’re a relatively new trend in fishkeeping.

People usually use these tanks in their office, apartment, or home as a small and exciting mini-ocean to improve their aesthetics or as a project.

Pico tank ownership is increasing around the world every day. If you’re wondering what they are or if they’re for you, this article should answer all your questions.

Check below for what a pico tank is, its pros and cons, what you need to set them up, and what you can put inside. We also included an FAQ section for any questions you might have.

Let’s begin, shall we?

What is a Pico Tank?

A Pico tank is the smallest aquarium tank possible. Because these awesome tanks and their water quantity are small, they require a lot of patience and care to maintain.

Take note:

Many pico tanks contain a maximum of 5 gallons, and even though they require more attention than other more enormous aquariums, the maintenance time is minimal.

Generally, we don’t recommend you put large fish in your pico aquarium as they can’t contain them. You will find that many hobbyists with a pico aquarium usually put only coral or smaller invertebrates like crabs, snails, and shrimps.

You will find hardy corals, hermit crabs, live rocks, and marine snails in most of the pico tanks you will encounter. Many initially thought that keeping coral reefs in small water volumes was impossible, but this has proven otherwise in recent times.

You might be wondering:

A lot of the people that keep a pico tank are professionals. This is because they have the required experience for taking care of one.

It leaves only a little room for error, and newcomers can make mistakes in maintaining it that could be devastating.

Advantages and Disadvantages of Pico Reef Tank

Check out some of the pros and cons of getting a pico tank:


  • Very cheap to set up, especially if you’re reusing equipment
  • Smaller equipment will help you save on electricity costs and purchase costs
  • Water changes are more affordable since you use less salt mix than larger aquariums
  • You do not need to reorganize your room or area to fit it, and you can keep it almost anywhere, including kitchen counters, nightstands, and bedroom dressers.
  • There is the freedom to choose different shapes and sizes to fit your room; it can be as creative as you want.
  • Maintaining it could be less challenging than larger tanks when you want to clean hard-to-reach areas.


  • You need to perform water parameter tests regularly to ensure water stability.
  • It would help if you did water changes at least once or twice a week
  • Tank inhabitants’ options are limited as you can only keep coral, tiny fishes, and invertebrates
  • Small tank size can make life support and hiding filtration challenging
  • Water conditions could change rapidly because of the small volume

Selecting from the Types of Pico Reef Aquariums

Before, any pico aquarium would have the shape of a glass container or a tiny vase; however, today, there are many more options. It would help if you made your selection based on where you intend to keep the tank and the equipment you have.

Check below before selecting a pico aquarium for your home

Small Consumer Tanks

These are simple tanks that look like regular aquariums with essential equipment.


  • Price isn’t as expensive as a mini complete tank
  • You have essential equipment in the tank, and you do not need to buy extra except you have unique needs.


  • The advertisement shows that they can hold the biological load of fish which isn’t true.
  • Equipment is unreliable and cheap sometimes.

Reef Jars and Containers

These are simple containers or jars that you can use for a pico tank. Their shapes might be irregular and unique and might not come with any equipment.


  • It is inexpensive, especially if you plan to reuse your former equipment or buy a little
  • Many everyday objects such as fishbowls, candy jars, and other glass containers are awesome examples of these that any local store will have.
  • You have the option to choose the volume of water and the shape of your desired tank.


  • Limited filtration options except you use up space for displaying corals. Some people add a smaller tank with plants for biological filtration and improve aeration.
  • Equipment might make it difficult to use space in the tank efficiently.

The Mini complete Tank

This tank looks like a regular aquarium and usually comes with equipment as a complete unit. You can buy it from Amazon or fish stores as an entire unit that doesn’t need much assembling.


  • People are increasingly using this tank which means you have enough resources and quickly get advice on any challenges and maintain the tank properly.
  • You will power all of the tanks with a single plug connected to a dock and power all the equipment in the unit.
  • The equipment is inside the sump, so it is not visible in one look. This sump also functions as an area that holds half of the tank’s volume to help biological filtration.
  • You can do quick water changes with the sump because it is effortless to remove and place back into the unit.
  • This unit comes with all the equipment you might need to get it running. The only thing not in the pack is the corals and saltwater.


  • Water circulation is usually between the main tank and sump, which does not allow much flow.
  • The heater in the unit is not usually accurate, so you might have to purchase a temperature regulator.
  • It costs between $60-90, which is higher than consumer and jar tanks.

Best Corals for Pico Reef Tanks

Only a few corals out of the many types can fit in a pico aquarium, and many of them are soft corals since hard corals need bright light conditions. You might also need to dose nutrients and keep stable conditions for many of these fishes.

Check out the best corals for a pico tank:

Mushroom Coral

Like the other corals on this list, Mushroom coral does not need bright light and is generally hardy considering the size of the tank. This coral will reproduce fast and move around the tank slowly.

You should know:

It is essential to keep an eye out for them as they move into another coral’s area.


These are among the most common options for a reef aquarium, and it’s not hard to see why. They are hardy and tend to grow very fast. Another essential advantage of this coral is that they are tolerant to condition changes.

Pulsing Xenias

Putting this coral in your tank will brighten it up and make it look very lively, contributing to producing light water flow.

Take note:

These corals have a reputation for spreading quickly in a tank and covering up all the available space. You should separate the corals from the primary rock in the tank and trim them to keep this in check.

Leather Toadstool Coral

It would help if you kept this coral in a tank with at least a modest flow. You don’t have to worry much about the water conditions as it is tolerant and adapts well to low light. If you’re new to this coral, you might notice unusual skin covering the polyps. You don’t need to worry about this as it is natural for their growth process and will only last for a week.

Green Star Polyps (GSP)

Green star polyps are one of the hardiest corals you’ll find out there. They also reproduce fast, and you will have to cut them back once in a few months, especially since it’s a tiny tank.

Top Fish for Pico Reef Aquarium

Any fish you put in a pico aquarium should be small enough to fit it with little maintenance. Examples of such fishes are:

  • Panda Goby
  • Two spot blenny
  • Bumblebee shrimp
  • Neon Goby
  • Hectors
  • Flaming prawn goby

Necessary Equipment for Pico Reef Aquariums

Here are a few pieces of equipment for maintaining a pico aquarium.


You need intelligent, reliable lights if you plan on keeping corals or small fishes in your tank. Many LED lights can fill this need, and there are many options available that will match your style and budget.

The two most popular LED lights used in most pico aquariums are A8- from Kessil and Prime 16HD from Aqua Illumination.

It would help if you went for a controllable light that gives excellent coral growth and excellent color. It is also great if you can mount it so it can fit many setup varieties.

Temperature Control

One of the critical considerations in keeping a pico tank is maintaining a constant temperature. Since the volume of water is minimal, it can easily be affected by the surrounding room temperature, and it can change in a short while.

This is by far what has caused many pico tanks to fail.

The area you are planning to place your pico aquarium also plays a role in this as there are places where you need extra precautions to make sure the water doesn’t get too cold or hot. Checking helpful tips can help you better understand all you need to do.

There are two devices for maintaining the temperature in a pico aquarium, namely:

Heater: These prevent the water from becoming too cold. They are digitally controlled and will come on and off depending on the temperature of the water.

Put a temperature range (usually 78 – 80 oF ), and it will automatically regulate. Since it is for a pico tank, you should only focus on heaters below 50 watts.

Chiller: If you live in a warm climate, this could prevent the tank water from getting too hot due to the surrounding temperature. When this device senses that the water is too hot, it will automatically cool it to the set range.

Live Sand and Live Rock

Space is limited in a pico aquarium, so you need to provide enough surface area for bacteria to cover and form a biological filter. Live rock and live sand can help you do that, and they are filled with beneficial bacteria to allow the tank to filter the water.


You can use small pieces of live rock rubble to create amazing aquascapes in your tank, even considering it is a small area.

Water Movement

Corals need random flow in the tank, and limited space might make that difficult to achieve. You can use the following to help with that:

Micro Wavemaker: This is a micro DC-controlled wave maker that you can program and set based on your needs. Its small size lets you place it anywhere without obstructing anything in the tank.

Rotating Nozzle: This is a simple device that fits the outlet nozzle of a filter return pump. It uses the flow from the pump to turn the offset nozzle and form a swirling flow pattern in the tank.


How big is a pico tank?

A pico tank is the smallest type of mini reef and ranges in size of about 2.5 gallons or less. Some pico tanks are as big as 5 gallons, but no more as anything bigger is a nano tank.

How small can a reef tank be?

A reef tank has most of the invertebrates, fish, and corals in an ocean’s natural coral reef. These aquariums are typically full of life, and the rocks present in them are also called live rocks.

The difference between a reef tank and traditional marine aquariums is that a regular saltwater tank will have coral skeletons and fish for decoration. A reef aquarium will have anemones, corals, and other aquatic invertebrates, and living organisms.

Reef tank size depends on the type as there are more significant and smaller-sized reef aquariums. As such, there is no specific type of reef tank size, and you can find one in almost any size you want.

What is the difference between a pico tank and a nano tank?

Nano tank is a mini reef that is one of the smallest but still bigger than pico tanks. Nanos range in size from 2.5 gallons to 30 gallons. Some nano tanks even reach sizes of up to 40 gallons. On the other hand, Pico reefs are the smallest types of aquariums you can find, as earlier explained.


Pico reef tanks are comfy aquariums that you can place almost anywhere. Their unique shapes give them a versatility that other bigger tanks do not have, and they will be beautiful additions to help beautify anywhere.


Beginners to the fishkeeping hobby should stay away from them until they have gathered a little experience to avoid mishaps. If you are planning to get one, you should be aware of the limited options you have regarding tank inhabitants.

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