How to Use Fish Water to Water Plants


If you own a freshwater fish tank, then you're already aware of the need to change water regularly to keep your fish healthy, but what few people know is that the water can be recycled for plants. Using fish water to water plants can add an extra shot of nutrients to your plants' soil because of the fish waste. Because the fish waste is already in liquid form, it's easy to apply to any plant.

Step 1

Plan to water houseplants and/or outdoor plants with fish water in place of, rather than in addition to, a regular watering, or you may drown your plants. Try to plan so that the two events occur together.

Step 2

Put a small bucket or large cup into the fish water and fill it with water. Pour the water into your watering can, but take care to only fill it as full as you can easily carry.

Step 3

Water your plants along the soil level at the base of the plant; avoid wetting the foliage and leaves. Add water to the plants until there is no fish water left or your plants are well watered.

Step 4

Water your plants with fish water as often as once a month, using regular watering as needed to keep the plants healthy between applications of fish water.

Tips and Warnings

  • If you have recently treated your fish tank for diseases, you should discard the water to avoid adding the medicine in your tank to your soil.

Things You'll Need

  • Fresh waste water in a large bucket
  • Large cup or small bucket
  • Watering can


  • "Tropical Fish"; Bruce W. Halstead and Bonnie L. Landa; 1975
  • "Reader's Digest Illustrated Guide to Gardening"; Carroll C. Calkins; 1993
Keywords: how to use fish water to water plants, how to water plants with aquarium water, watering plants with fish water

About this Author

Margaret Telsch-Williams is a freelance, fiction, and poetry writer from the Blue Ridge mountains. When not writing articles for Demand Studios, she works for as a contributor and podcast co-host.