How to Clean Fish Tank Decorations

Why Fish Tank Decorations Need Regular Cleaning

Aquarium decorations — rocks, driftwood, plastic plants, caves, and ornaments — accumulate algae, biofilm, and debris over time. While a thin layer of biofilm is harmless, heavy algae buildup looks unsightly and can harbor harmful bacteria. Regular cleaning keeps your decorations looking great and your tank environment healthy.

How Often Should You Clean Aquarium Decorations?

• Light algae wipe: Weekly, during your regular water change
• Deep clean: Every 4–6 weeks, or when algae buildup is visible
• New decorations: Always rinse before adding to the tank

What You Need

• A bucket of old tank water
• Soft brush or old toothbrush
• Clean cloth or sponge
• Hot water (for deep cleaning outside the tank)

For plastic plants and decorations, the PietyPet Aquarium Plastic Plants are easy to clean — simply remove and rinse. Unlike live plants, they require no special care and can be scrubbed without damage.

How to Clean Fish Tank Decorations Step by Step

Method 1: In-Tank Cleaning (Weekly)

For light algae, use a soft brush to gently scrub decorations while they're still in the tank. The loosened algae will be caught by the filter or vacuumed up during your water change. This is the least disruptive method and works well for routine maintenance.

Method 2: Out-of-Tank Cleaning (Monthly Deep Clean)

1. Remove the decoration from the tank and place it in a bucket of old tank water.
2. Scrub with a soft brush — an old toothbrush works perfectly for crevices and textured surfaces. Use only water — never soap, bleach, or household cleaners. Even trace amounts are toxic to fish.
3. Rinse thoroughly with hot water to remove loosened algae and debris.
4. For stubborn algae: Soak the decoration in a solution of 1 part white vinegar to 3 parts water for 10–15 minutes, then scrub and rinse thoroughly with plain water before returning to the tank.
5. Return to the tank once clean and fully rinsed.

Cleaning Live Rock and Natural Decor

For natural materials like lava rock or driftwood, scrub gently with a brush in old tank water only. Avoid soaking in vinegar — it can alter the pH properties of porous natural materials.

What NOT to Use When Cleaning Decorations

• ❌ Soap or dish detergent — toxic to fish even in trace amounts
• ❌ Bleach — unless doing a full sterilization with thorough rinsing and dechlorination after
• ❌ Boiling water on resin or plastic decorations — can warp or crack them
• ❌ Abrasive scrubbers on painted or coated decorations — can remove the finish

Tips to Keep Decorations Cleaner Longer

• Reduce lighting to 8–10 hours per day to slow algae growth
• Keep nitrate low with weekly water changes — test with the Varify 17-in-1 Water Test Kit
• Add algae-eating snails or plecos to your tank
• Don't overfeed — excess nutrients accelerate algae growth on all surfaces

Final Thoughts

Cleaning fish tank decorations is simple when done regularly. A quick weekly brush during your water change prevents heavy buildup, and a monthly deep clean keeps everything looking fresh. Always use water only — never soap — and your decorations will stay beautiful for years.