19 Unique Fish Tank Themes To Use In Your Aquarium!

One of my favorite things about the fish-keeping hobby is the ability to customize your aquarium to fit your style.

Whether you’re drawn to classic biotope themes or prefer something like superheroes or dinosaurs, the possibilities are endless.

After seeing several people reaching out and asking for some unique fish tank themes, I published this article going over some of the more popular themes in the hobby.

Avengers Theme

Avengers theme
Avengers Theme

The Avengers and the wider Marvel Cinematic Universe are among the most popular franchises in the world.

This has inspired many enthusiasts to theme their fish tanks around superheroes.

You can create a group-based theme by focusing on the Avengers or the Justice League. Alternatively, you can focus on a single superhero for your tank such as Spiderman or Superman.

There are plenty of aquarium-safe superhero figures on the market. Get a few of these, and add them to your aquarium.

Begin by scaping your tank with substrate, rocks, and hardscape until you’re satisfied with the layout. Once everything is in place, add your superhero figures and enjoy your themed aquarium.

Biotope Themes

Biotope Themes
Biotope Themes

Biotope themes are becoming increasingly popular in the fish-keeping hobby but can be expensive.

Biotope tanks replicate the natural environment of your fish, including the substrate, plants, rocks, and invertebrates.

The increased availability of botanicals, natural rock, wood, and substrate from regions like South America and Southeast Asia has made creating biotopes far easier than before.

Plan your tank and ensure everything fits your budget before purchasing your equipment and prices can quickly spiral out of control.

Dinosaur Themed

Dinosaur Themed
Dinosaur Themed

I remember one of my friends having a T-Rex in his aquarium when the original Jurassic Park was released and Dinosaur-themed fish tanks are more popular than ever.

This theme can be as simple or complex as you like, and even the simpler setups can look impressive when done correctly.

Broad-leaf plants are essential for this tank, as they resemble the large ferns in movies like Jurassic Park. The following plants are ideal for a dinosaur-themed tank:

  • Anubias
  • Crypts
  • Echinodorus
  • Java Fern

You can use additional plants for detailing, but these are easy to maintain and perfect for creating a dinosaur jungle theme.

Disney Themed

Disney Themed
Disney Themed

Disney-themed aquariums have always been popular due to the huge range of characters you can choose, making it easy to find something that appeals to everyone, regardless of age.

For a desert-themed tank, Aladdin would be a fantastic choice. If you prefer a jungle theme, consider Tarzan or The Jungle Book, Lilo & Stitch or Moana are perfect for a tropical setup, while Tron works for a futuristic theme.

The variety of themes under the Disney brand is so extensive that it could warrant its own article.

Here’s a list of all Walt Disney movies to help you find the perfect theme for your aquarium. Choose a movie to base your tank on, set it up, and add figures from that specific movie and you are good to go.

Hello Kitty

Hello Kitty
Hello Kitty

The Hello Kitty franchise has a huge fan base, making it a fantastic theme for fish tanks.

This theme can easily be adapted for aquariums, and in 2011, there was a trend in Japan to create beautiful Hello Kitty pico tanks.

I’ve seen people add a couple of Hello Kitty figures to a standard planted tank with great results, keeping costs low while still achieving the theme.

Alternatively, you can go all out and cover your aquarium with Hello Kitty items to fully embrace the theme.

Jungle Theme

Jungle Themed
Jungle Themed

The jungle-themed tank is one of my favorites because it’s cheap and easy to create. It also complements a variety of popular fish, making it a great choice for many aquarists.

Instead of trying to replicate the exact look of a jungle, this theme focuses on allowing plants to compete for space, nutrients, and light, just as they would in the wild. As the plants grow, the tank develops a lush, thickly planted appearance.

This theme is beginner-friendly due to its low maintenance requirements, and the dense plant growth can conceal common beginner mistakes. Here are some easy-to-grow plants suitable for a jungle-themed tank:

  • Anubias
  • Crypts
  • Echinodorus
  • Hygrophila Polysperma
  • Java Fern
  • Rotala Rotundifolia
  • Vallisneria

Another advantage of this theme is that hardscape elements are less important than in other aquascapes.

As the plants grow, they often cover the hardscape, allowing you to skip it altogether and keep costs down.

Lego Themed

Lego Themed
Lego Themed

Lego tanks are controversial but when done correctly, they can be both visually appealing and safe for your fish.

Considering that lava rock can have sharper edges than Lego blocks, I don’t understand the controversy.

I haven’t used Lego in my tanks but I’ve seen several impressive examples on social media. A Lego-themed tank can range from using a few Lego blocks as key focal points to completely decking out the entire tank with Lego structures.

A full Lego setup usually needs a decent filter to maintain safe and stable water parameters for your fish.

Mario

Mario Themed
Mario Themed

Mario is one of the biggest gaming franchises ever, so it’s no surprise that it’s a popular theme for fish tanks.

One of the best aspects of a Mario-themed tank is that you can set up your aquarium with plants as usual, then add Mario mushroom figures in various spots to give it that distinctive Mario touch. You can even take it further by adding figures of different characters from the Mario games.

This theme offers a great opportunity for creative individuals to express themselves and showcase their skills, given the broad and imaginative possibilities of the Mario universe.

Minions Themed

Minions Themed
Minions Themed

Minions are another fun and easy fish tank theme that can add a vibrant splash of color to most setups.

Start by adding your substrate and hardscape, then plant the tank. Finally, include a few Minion figures for a striking impact.

Packs of Minion figures are usually cheap and aquarium-safe, making this an excellent option for beginners.

I’ve seen Minion figures on Amazon that are perfect for nano tanks. Larger Minion figures are available for bigger tanks but their prices can increase significantly.

If you have the budget, you can fill your aquarium with Minion figures of all sizes to fully embrace the theme.

Mountain Themed

Mountain Theme
Mountain Theme

Mountain-themed fish tanks have always been popular because they offer a stunning aquascape that is easy and affordable to create.

I’ve seen some beautiful mountain aquascapes that use cheap inert gravel for the substrate, Seriyu Stone for the mountains, and java moss for detailing.

This setup may sound simple, but when setup correctly, it can look amazing—the key is that less is more when it comes to the moss.

You can add various epiphyte plants to take the aquascape to the next level. Anubias and bucephalandra are ideal choices, but you can also try java fern or Bolbitis heudelotii.

Pirate Theme

Pirate Theme
Pirate Theme

Pirate-themed fish tanks have always been popular and there are plenty of cheap pirate kits on the market.

You can use a shipwreck decoration as the centerpiece and add other pirate-themed items to complete the look. 3D-printed pirate-themed figures work well in this aquarium and are usually cheap.

Prioritize swim space for your fish by getting your pirate decorations before ordering your fish. This way, you can add everything to the tank and make necessary adjustments.

The last thing you want is a group of shoaling fish with limited swim space because the decorations take up too much space.

Pokemon Themed

Pokemon Theme
Pokemon Theme

Pokemon is one of the most popular franchises ever, with over 1,000 individual Pokemon that can be used to create a themed fish tank.

I have a dedicated article on Pokemon fish tank ideas, as there are countless possibilities. The best part is that this beginner-friendly project can look fantastic without breaking the bank.

Many Pokemon figures are aquarium-safe, and the 3D-printed figures available online are often suitable for use in aquariums.

With so many Pokemon, you can easily customize a theme specific to your style.

Danish Themed

Red Plant
Red Plant

Danish-themed tanks focus on using red plants, with minimal green plants in the tank.

I prefer to use small splashes of red to maximize the effect but this style is becoming increasingly popular among fish keepers and aquascapers.

The “Danish style” uses no green plants and is believed to originate from the red in the Danish flag or from the person who popularized this style being from Denmark.

Regardless of its origin, the goal is straightforward: incorporate as many red plants as possible into your tank.

However, this can be challenging for beginners, as red plants are typically more difficult to maintain than green ones.

They often require specific fertilizers and suitable lighting, which can increase the overall cost of your tank.

Reef Tank Themed

Reef Tank Themed
Reef Tank Themed

The freshwater reef tank theme is starting to decline in popularity, but it was once a surprisingly popular choice among hobbyists.

I love keeping live plants in my tanks, so I have never actually set up a tank with this theme, but I know two friends who have had similar setups.

This theme is relatively simple: purchase your substrate and rocks, arrange them in your tank, and decorate with fake coral and anemone decorations.

One potential issue is that the more realistic coral decorations can be quite expensive compared to the cheaper options.

Additionally, the absence of real plants in the tank usually necessitates a good filter to maintain safe and stable water parameters for your fish.

Spongebob Themed

Spongebob Themed
Spongebob Themed

SpongeBob SquarePants is often seen as a meme in the hobby, but it plays an important role.

Attracting young people to fishkeeping can be challenging, but the SpongeBob aquarium set helps introduce them to the hobby.

The high number of reviews on Amazon indicates that SpongeBob decorations sell in massive quantities year after year, and have done so for a long time.

Social media is also filled with countless photos of people using the SpongeBob kit, showcasing its popularity.

While experienced adult fish keepers might joke about this theme, it’s important to recognize the valuable role it plays in bringing new enthusiasts into the hobby.

Spooky Themed

Spooky Themed
Spooky Themed

Spooky aquarium themes are becoming increasingly popular and are relatively easy to create.

Unlike Halloween themes, which focus on pumpkins, haunted houses, and ghost decorations, spooky themes use driftwood and plants to achieve the desired look.

This type of aquarium is typically a long-term project, allowing your fish to settle into their environment, rather than being a temporary setup like Halloween themes.

Adding leaf litter and botanicals to your tank can introduce tannins, darkening the water and enhancing the spooky effect.

Affordable hardscape like spider wood works well helping to keep costs down but other types of wood can also be effective.

Star Wars Themed

Star Wars Themed
Star Wars Themed

Star Wars is one of the most popular franchises ever, offering plenty of characters that make for an excellent aquarium theme.

One of the great advantages of a Star Wars-themed aquarium is the abundance of merchandise on the market.

This makes it easy to find core decorations for your tank, with modern, aquarium-safe products often being more affordable than older, collectible items.

I’ve seen some epic Star Wars fish tank setups on social media.

Like the other themes mentioned, these setups work well with live plants. For instance, anubias, crypts, echinodorus, and java fern create a lush, jungle-like environment, perfect for hiding Star Wars decorations and giving the illusion of a jungle planet.

Underwater City Themed

Underwater City Themed
Underwater City Themed

Underwater cityscapes are visually stunning and often easier to create than people expect.

One of the simplest ways to achieve this look is by using tabletop gaming buildings for your cityscape.

Many of these buildings are aquarium-safe, and offer a high level of detail at a low price. While custom 3D-printed cityscapes look incredible, they can be quite expensive.

After placing your building in the tank, it’s time to add plants.

For this theme, less is usually more. A few strategically placed patches of moss can create the impression of a lost city or a post-apocalyptic setting without overdoing it.

Underwater Forest Theme

Underwater Forest Theme
Underwater Forest Theme

The underwater forest theme can be stunning if setup correctly.

Finding the right driftwood can be challenging, so people often choose other styles instead. Unlike the jungle theme, where overgrown plants dominate, the forest theme highlights visible driftwood with plants serving as complementary elements.

Top-down plants work well in this setting, and Amazon Frogbit floating on the surface is a great choice.

Adding moss high on the driftwood near the surface enhances the forest look, while anubias, crypts, and sword plants are excellent options for this type of aquascape.