The short answer
Clean décor by rinsing and scrubbing it in old tank water — the water you’re already removing during a water change is perfect. The one rule to never break: no soap, no detergent, no household cleaners. Even a tiny residue is hard to rinse out and can poison fish. For everyday grime, a pad or old toothbrush and some tank water is all it takes.
The safe routine
- Time it with a water change. When you drain water into a bucket, use that bucket to swish and scrub ornaments, plants and rocks. It cleans them without exposing beneficial bacteria to tap water.
- Scrub, don’t dunk in tap. An algae pad or a dedicated old toothbrush lifts algae and film. Avoid blasting porous décor under a hot tap, which can kill the helpful bacteria living on it.
- Rinse and return. Give items a final swish in the same tank water and put them straight back.
For stubborn buildup
If algae or limescale has really taken hold, a longer soak in a bucket of tank water loosens it before scrubbing. Some experienced keepers use a heavily diluted bleach soak for badly fouled ornaments, but that’s an advanced step that demands a very thorough rinse and a strong dose of dechlorinator before anything goes back in — for almost everyone, elbow grease and tank water is enough.
Tools and next steps
An algae pad or magnet keeps décor and glass clear between cleans — see our magnet cleaner picks. Do this alongside your water change with a gravel vacuum, and browse all maintenance gear. For the full routine see how to do a water change, and if décor is turning white with scale, see removing limescale.