How to theme your aquarium – 4 great decor ideas for your tank

The most eye-catching and impactful aquatic displays are often the ones that follow a theme. Here’s some easy to create decor themes to make your tank look spectacular. 

Flooded forest

Few tanks look more natural than one simply decorated with fine sand, wood and with brown, tea-stained water. “Blackwater” habitats are common around the world and many of the fish we keep from Cardinal tetras to Pearl gourami to Dwarf cichlids naturally inhabit blackwater in the wild. 

The water is stained brown from the tannins released by fallen food and leaves from the forest canopy above and blackwater fish often have striking markings or bright, iridescent colouration so that they can see each other in the gloom. Tannins make the water soft and acidic so by using wood, leaves and blackwater in the aquarium you can make many soft water species feel right at home. 

Get the look

Fit a black background to the tank, use soft, inert, lime-free sand on the bottom and add more than the usual amount of bogwood pieces. Keep lighting and filter flow subdued and either leave plants out entirely or hang some jungle looking artificial plants upside down to replicate the forest canopy. 


Many people want their tank to look marine but either don’t have the budget or dont want the hassle of a full-on saltwater aquarium. You can make a freshwater tropical aquarium look like a marine tank however by following these few easy steps. 

Get the look

Use coral sand on the base to simulate that pristine desert island sand and use artificial reef rock to give you that creamy coloured rock structure that makes saltwater tanks stand out. Decorate with artificial corals and marine themed ornaments and use vivid blue and yellow cichlids from Lake Malawi to complete the look. Note coral sand and reef rock raises the pH of the water so this style of tank doesn’t suit all types of freshwater fish. Stick to Malawi cichlids as they prefer hard alkaline water and rocky, limestone habitats. 

Reef rock can give a saltwater look to a freshwater tank


Hardcore aquarists may turn their noses up at this one but done properly they can look really impactful and engage younger fishkeepers and non-fishkeepers alike. Let your creative imagination run wild and create the kind of colourful, fun, fantasy underwater landscape that’s full of movement and bubbles, just like in a Disney animation.

Get the look

Connect a powerful airpump to two or more long airstones and place these down first, securing them with airline clips and suckers. Use blue gravel for the base or section the tank off using yellow gravel in one part to simulate sand, or different grades and shades of blue and green gravels to create a fantasy seabed. Use coloured rocks, bright artificial plants and action air-powered ornaments like divers and sea chests that bubble and move, as well as a big shipwreck ornament.

Top the look with a blue background and a community of brightly coloured, different shaped fish-like Angelfish, gouramis, platies, albino corydoras gold rams. It’s a long way from the wild but the fish are tank bred and won’t mind one bit. Its a tank you won’t be able to keep your eyes off.

Nature aquarium

The Nature Aquarium term was given to Japanese styled planted aquariums which used neatly placed rocks, wood and mosses to recreate terrestrial mountains, meadows and forests as we see in nature. Think bonsai trees or the Chelsea Flower Show underwater and with the help of bright lighting, CO2 fertilization and liquid fertilisers you can have your own contemporary Japanese underwater garden at home and tend to it with delicate tweezers and stainless steel scissors. 

Get the look

Invest in a rimless aquarium with super clear OptiWhite glass and bright lighting. Use aquascaping soil and select wood and rocks to create the hardscape, then plant a carpet of low growing plants which will cover the soil like a lawn and produce silvery bubbles as they photosynthesize. Top the look with a shoal of a single species of tetra and some algae eating shrimp.   

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Jeremy Gay is an author, lifelong fishkeeper, and aquatic specialist. He's a former editor of Practical Fishkeeping Magazine, UK editor at Reefbuilders, a former aquatic store manager, and has collected fish in Sri Lanka and the Amazon. He's been on tv and radio, contributed to Koi Carp and Gardeners World magazines, been a product tester, a judge, and a product developer. Jeremy is here to guide and advise you on all things tropical, pond and marine, from set-up to stocking, health, feeding to breeding, as well as solving many common fishkeeping problems along the way.

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