Avoid these mistakes when choosing aquarium decoration

A good aquarium decoration not only pleases our eyes but also is functional for our fishes. But not everyting we can get into our aquarium is good for its inhabitants. Especially if you are a beginner in this great hobby, you should follow these tips for decoration selection.

This article is exclusively about decorations for feshwater aquariums.

Overview of aquarium decorations

There is a lot of decoration you can buy for your tank. We will discuss these various items below. But here you already get a short overview:

  • Roots & branches
  • Stones
  • Caves
  • Artificial plants
  • Aquarium background foils
  • 3D backgrounds

Decoration in Detail

Roots & branches

  • Material: Morkia wood, mangrove wood, moor wood
  • Price: small pieces ~ 20 €, middle ~ 40 €
  • Possible mistakes: The wood must not contain any metallic inclusions, as these are not tolerated by fish and especially by shrimp. Do not try to use branches or roots from your garden. The danger that they are decompositing and contamine your water is too big.
  • Before inserting: Depending on the type of wood, the root will probably not stay on the ground initially and float instead. To fix that you can sink the root in a water filled bucket weighted with a stone for a while. After about a week, the root should be ready that it can be placed in the aquarium without extra weighting. The technique with a separate bucket has also the benefit that all pollutants can be discarded along with the bucket water.
  • Advantages: Roots also occur often in the natural habitat of our fish and thus improve the housing conditions. In addition, good bacteria can accumulate on the surface.
  • Tips: In order to give the root a more appealing optic, you can fix plants such as Anubien, ferns or mosses. These are tied with a nylon thread and when the plant has fixed itself to the root the thread is removed.


  • Material: Quartz, Slate, Lava stone
  • Price: Lava Caves Puzzle ~ 5 €, other stones 1kg ~ 5 €
  • Possible mistakes: Again, it is important to bring no objects with metallic inclusions into the aquarium, otherwise the aquarium inhabitants can die from poisoning. In addition, you should ensure that the stones you choose will not harden your water. You can easily test this by dripping concentrated acetic acid from the hardware store onto the stone. If it foams it is calcareous. If it does not foam you can use it without hesitation. Also make sure that the stone has no sharp edges as otherwise the fish could injure themself.
  • Before inserting: You should thoroughly clean stones before you give them to the aquarium.
  • Advantages: Stones can serve as hiding places or as natural territorial boundaries of various fishes.
  • Tips: Stones must be installed firmly so that they do not crush aquarium inhabitants when falling over. That’s why it’s best to set it up before adding the ground. That way the substrat is acting as additional fixation.

Caves & Hideouts

  • Material: Clay, Stone, coconut shell
  • Price: Small clay caves ~ 5-10 €, Large clay caves ~ 20 €. Cheap alternative: flower pot or coconut shell (clean well before)
  • Possible mistakes: Ready to buy clay or stone caves are usually harmless and you can not make a mistake. Be careful when dealing with plastic caves. If they smelled strongly of plastic, there might be excessive amount of plasticizer into it and these will get into the aquarium.
  • Before inserting: Can be used directly without preparation.
  • Advantages: Especially catfish and many cichlids need hiding places either for reproduction or for their well-being.
  • Tips: Try to distribute the caves well over the aquarium and offer a retreat even in hard to see places.

Artificial plants

  • Material: Plastic
  • Price: Per plant ~ 10 €
  • Possible mistakes: Since the plants are produced for use in aquariums, there should be no problems. But with plastic it must always be ensured that no inferior goods are used. Especially strong plastic odor can be a sign of unsuitable material.
  • Before inserting: Can be used directly without preparation.
  • Advantages: Some fishes like to destroy real plants so the only alternative is to get artificial plants.
  • Tips: For most aquariums it is advisable to use a relatively dense marginal planting and to leave the middle swimming area free.

Background foil

  • Material: Foil
  • Price: Foil for 60x30cm² ~ 3-5 €, Foil for 120x40cm² ~ 4-7 €
  • Possible mistakes: Because the foil is placed outside of the aquarium there is no danger to the fishes.
  • Before inserting: Can be used directly without preparation.
  • Advantages: Depending on your taste, the back of the photo gives you a more beautiful look.
  • Tips: When it comes to adhesive films, start at the short edge and slowly roll the film over the glass and spread out the bubbles as soon as they are appear.

3D backgrounds

  • Material: Plastic
  • Price: Rear wall for 60x30cm² ~ 20-40 €
  • Possible mistakes: The back wall must of course be firmly mounted. Keep in mind on the rough surface of the wall algae easily grows and that with a 3D wall you loose volume for the fishes. For small aquariums you should make up your mind if you really want a 3D wall or better stick to a background foil.
  • Before inserting: Can be used directly without preparation.
  • Advantages: You can hide parts like filter and heater behind a 3d wall and the optical effect is very nice.
  • Tips: The 3d background should be placed in the aquarium ahead of all other objects. For gluing use either silicone (without additives such as Fungizit) or special glue for fish tanks such as Conexo from Juwel.

No-go decoration

  • Everything from the sea (e.g. mussels, dried starfish, etc)
  • Things that can rot (e.g. undried branches from the garden)


I hope the overview could show you the most important sources of mistakes when it comes to buying aquarium decoration. However dont pack the aquarium too much with decoration since many fish need enough free swimming space.

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