Minecraft Aquarium: How to Build an Aquarium in Minecraft

A Minecraft aquarium can turn an empty wall, bedroom corner or large room into a living underwater display. The basic idea is simple: build a glass tank, fill it with still water add lighting and decorations then add fish.

The tricky parts are creating a tank that does not leak, converting the water into still source blocks, keeping coral alive and choosing decorations that leave enough swimming space. 

This guide explains how to make an aquarium in Minecraft step by step from choosing the size and materials to adding fish, coral, axolotls and custom designs.

What You Need for a Minecraft Aquarium (Fish Tank Materials)

You do not need a huge list of materials for a basic fish tank in Minecraft. The main requirements are glass, water, floor material, lighting and buckets for collecting fish.

Buckets require three iron ingots each. Fill a bucket with water, then use the water bucket on a fish to collect it. After you release the fish, the bucket becomes empty again, so you need to refill it before catching another fish.

Step 1: Choose the Size and Shape

Decide where your Minecraft aquarium will go before placing the first block. The most important measurement is the inside size because the walls and floor need additional space.

These examples refer to the usable interior, not the outside dimensions. A 3 × 2 × 2 interior is enough for a small decorative tank. A 5 × 3 × 3 tank gives you more room for plants and several fish, while a larger aquarium works better as a room divider or centrepiece.

For a rectangular tank, measure the floor first and leave enough room around it to access the top. If you want a round aquarium, plan the outline before building the walls. An odd diameter circle usually gives you a clearer centre point and makes symmetrical designs easier to build.

If the aquarium is part of a house, plan its position with the rest of the room. Our Minecraft house blueprints can help when deciding where a feature wall or built in aquarium would fit. For a bedroom build, Minecraft bedroom ideas can also help you integrate the tank without making it look like an extra box attached to the wall.

Step 2: Build the Aquarium Tank

Build the floor first, then construct the back and side walls. Add the front glass last if you want easier access while decorating.

Leave the top open during construction. You can close it after the water, lighting, plants, and fish are ready.

For the main viewing wall, full glass blocks are usually the better choice because they provide a continuous surface and a clear view of the tank.

Should You Use Glass Blocks or Glass Panes?

Glass panes can be waterlogged, but their thin shape can cause small fish to get caught around the edges. Full glass blocks give you a cleaner viewing wall and are the safer choice for a fish tank in Minecraft.

Check every corner before filling the tank. A single missing block can allow water to escape and leave part of the aquarium empty.

In Creative mode, the fill command can build a large glass shell in one go. Our Minecraft fill command guide covers the Java and Bedrock syntax.

Step 3: Fill the Minecraft Aquarium With Still Water

The easiest way to create a large body of still water is the kelp method. The important part is starting with water at the top of the column rather than trying to build the water upward from the floor.

The Kelp Method

Follow these steps:

1. Fill the top layer of the aquarium with water source blocks.

2. Place kelp on the floor directly below the water.

3. Grow the kelp upward until it reaches the water surface.

4. Break the kelp after the column has been filled.

When kelp grows through downward-flowing water, the water blocks in the column become source blocks. After you break the kelp, the source water remains in place.

Repeat this process across the entire tank. For a small aquarium, manually placing water source blocks can also work, but the kelp method saves time in taller or wider builds.

Kelp can continue growing after the water is finished, so trim it if it starts covering the viewing area. Use seagrass for shorter foreground plants when you want more control over the composition.

If you are building an aquarium beside a larger water feature, a Minecraft pool guide can help with the surrounding design.

Step 4: Add Underwater Lighting

Lighting makes the fish and decorations in your Minecraft aquarium visible, but placement matters. Light does not pass through solid blocks, so burying a sea lantern completely inside a solid floor or wall will not properly illuminate the aquarium.

Leave at least one face of the light source exposed to the water or cover the light with a transparent block such as glass.

Sea lanterns are especially useful because they provide a strong light source while fitting naturally into underwater builds. Torches do not work as normal underwater lighting, so use water-compatible light sources instead.

For a cleaner appearance, place sea lanterns along the bottom or side of the tank where their light can reach the water. Covering a light with glass can also make it blend into the aquarium wall without blocking the light completely.

Step 5: Add Plants, Coral and Decorations

Once the water and lighting are finished, decorate from the floor upward. Avoid filling every block because fish need open water to move around.

Use sand, gravel, clay, stone or prismarine to create different sections on the floor. Add seagrass in open areas and use coral when you want stronger colours.

How to Keep Coral Alive?

Living coral needs water to survive. Keep at least one water block touching the coral, and waterlogged blocks can also provide the required water contact.

Without water, living coral turns into dead coral within a few seconds and cannot be revived.

Living coral and coral fans require Silk Touch to collect while keeping them alive. Coral blocks mined without Silk Touch drop as dead coral blocks. Warm oceans are a useful place to collect living coral because coral reefs naturally generate there.

Add Seagrass and Kelp Carefully

Seagrass works well in the foreground because it stays relatively short. Kelp can grow upward and eventually block part of the view, so use it in deeper background areas or trim it when necessary.

Add Decorative Blocks

Small stone, clay, sand, gravel, prismarine and slabs can create depth without filling the whole tank.

If you are building a curved aquarium, save the circle-planning links for the actual shape section rather than adding several generators here.

Step 6: Catch and Add Fish

Fish are collected with a water bucket, not an empty bucket. First, fill your bucket with water. Then use the water bucket on a fish to catch it. The fish is stored inside the bucket, allowing you to move it to your aquarium.

To release the fish, use the fish bucket on a block inside the aquarium. The fish will appear in the water and the bucket will become empty again.

Add only a few fish at first. This makes it easier to check the tank's size, decoration, and swimming space before adding more.

Fish You Can Add to a Minecraft Aquarium

A Minecraft aquarium can hold several fish types, from colourful tropical fish to cod, salmon, and pufferfish. Choose fish based on your tank size, design, and the look you want to create.

Tropical Fish

Tropical fish are a colourful choice for decorative aquariums. They commonly appear in warm and lukewarm oceans and lush caves. Java Edition also has tropical fish spawning in mangrove swamps.

Their many colour and pattern combinations make them particularly useful when you want a bright aquarium.

Cod

Cod has a simple appearance that works well in natural or survival-style tanks. It can also provide contrast when the aquarium contains colourful coral and tropical fish.

Salmon

Salmon have a pink-orange appearance and are a good option for larger tanks where you want a different fish shape and colour from tropical fish.

Pufferfish

Pufferfish add variety to an aquarium, but they can poison players when they become defensive. The main danger is when handling or releasing them, so use care when placing them in the tank.

Do Minecraft Fish Need Food?

No. Fish do not need to be fed to survive in an aquarium. Once they have been released into the tank, you can focus on keeping the water, lighting, and decorations in good condition.

Do Bucketed Fish Despawn?

Fish you release from a bucket do not despawn naturally. Wild fish that spawn naturally can despawn when you move far enough away. For a permanent aquarium, catch the fish with water buckets before placing them in the tank.

Minecraft Aquarium Ideas

Minecraft aquarium ideas can range from simple wall tanks to round aquariums and large walk through tunnels. The right design depends on your available space, build style and how you want the aquarium to fit into the surrounding area.

Small Wall Aquarium

A small wall aquarium works well in houses, bedrooms, libraries, and underground bases. Build a shallow glass tank into the wall and use exposed lighting along the floor or sides.

Round Aquarium

A round Minecraft aquarium gives you multiple viewing angles and works especially well as the centrepiece of a large room. 

For a cleaner circular shape, plan the diameter before building. An odd diameter gives you a clear centre block and can make symmetrical detailing easier. Use our Minecraft Circle Generator to plan the main outline .

Walk Through Aquarium Tunnel

A walk-through aquarium tunnel is a larger build where players move through a glass passage while water and fish surround the tunnel.

Build the tunnel through a large water-filled structure and make sure every section of the glass shell is sealed before adding the water. This design needs considerably more space than a normal wall aquarium, but it can become the main feature of a base or public build.

Can You Keep Axolotls With Fish?

Not safely. Axolotls can hunt fish and other aquatic mobs, so they are better suited to a separate display if you want your fish aquarium to remain peaceful.

For an axolotl tank, use moss, clay, stone, seagrass, and open water to create a cave like environment. Avoid filling the entire tank with decorations because axolotls still need room to move.

Java vs Bedrock: What Changes?

The main aquarium building process is the same in both editions, but fish spawning and some underwater mechanics can differ.

Tropical fish are found in warm and lukewarm oceans and lush caves in both editions. Java Edition also includes mangrove swamps as a tropical fish spawning location.

Tropical fish group sizes are another difference. Java Edition can spawn them in groups of 8, while Bedrock Edition uses smaller groups, including groups of 3 to 5 and smaller groups.

For most aquarium builds, these differences do not change how you construct the tank. They matter mainly when you are collecting fish from the world.

Common Minecraft Aquarium Mistakes

• Building the tank with gaps in the glass walls.

• Filling the tank with flowing water instead of creating source blocks.

• Starting the kelp method from the floor instead of placing the top water layer first.

• Completely hiding light sources behind solid blocks.

• Using torches as underwater lighting.

• Placing living coral without water touching it.

• Let the kelp grow until it blocks the viewing area.

• Adding too many fish to a small tank.

• Handling pufferfish carelessly while collecting or releasing them.

• Keeping axolotls with fish when you want a peaceful display.

Conclusion

Building an aquarium in Minecraft is straightforward once the water and lighting are handled correctly. Build a watertight glass tank, create still source blocks with the kelp method, use exposed underwater lighting, then add plants, coral, and bucketed fish.

Start with a simple rectangular design if this is your first build. Once the basic tank works, you can expand it into a round aquarium, wall display or walk through tunnel that becomes part of the surrounding build.

For more Minecraft building projects, explore our Minecraft building tutorials and use the Minecraft Java vs Bedrock guide when an edition-specific mechanic matters.

FAQ

How Big Should an Aquarium Be in Minecraft?

There is no required size. A 3 × 2 × 2 interior works for a compact display, while larger tanks give fish more swimming space and allow more detailed decorations.

What Is the Easiest Aquarium Design?

A rectangular glass tank is the easiest design for beginners. Build the floor and walls, fill the tank with still water, add exposed underwater lighting, then decorate it with seagrass and a few fish.

Can Coral Survive in an Aquarium?

Yes. Living coral survives when it has water touching it. Without water, it turns into dead coral after a few seconds and cannot be revived.

Do Fish Despawn in a Minecraft Aquarium?

Fish released from a bucket do not despawn naturally. Naturally spawned fish can despawn when the player moves far enough away, so bucketed fish are the appropriate choice for a permanent display.

Can You Build an Aquarium in Survival Minecraft?

Yes. A basic aquarium only requires materials such as glass, water buckets, lighting, and a few decorative blocks. Silk Touch is useful when you want to collect living coral.