Decor
Aquarium sand and gravel, rocks, driftwood, artificial plants and hiding places.
Decor does more than make a tank look good: it reduces stress by giving fish places to hide and increases the surface area where beneficial bacteria can settle. Caves, driftwood and dense planting are especially important for shy species and bottom dwellers.
Choosing a substrate
- Fine sand: ideal for fish that sift the bottom, such as corydoras, and kind to their mouths.
- Gravel: easy to clean with a siphon; choose rounded rather than sharp grains.
- Plant substrate: feeds live plants, though it can affect water parameters at first.
Limestone, coral and seashells raise hardness and pH. They suit hard-water species such as Malawi cichlids but not soft-water fish like neons or discus. If you are unsure, put a few drops of vinegar on a stone; if it fizzes, it contains lime.
Natural driftwood can release tannins that tint the water tea-coloured for the first few weeks; this is harmless and can be reduced by soaking the wood for a few days. Make sure artificial decor has no sharp edges, which can tear the fins of long-finned fish such as bettas. Rinse new decor in hot water, without soap, before use.
When arranging decor, leave open swimming space and seat heavy rocks firmly on the base rather than leaning them against the glass, since a toppling rock can crack a pane.
Common questions about Decor
Can I use stones I collected outdoors?
It can be risky, as they may contain lime, metals or chemical residues. Do a vinegar test and scrub and boil them; if in doubt, use aquarium-safe stone.
How much substrate do I need?
A 3–5 cm layer is enough with artificial plants; 5–8 cm for live planting.
Why is my driftwood turning the water brown?
It is tannin leaching from the wood. It is harmless and can be reduced with activated carbon or by pre-soaking the wood.