How to Make an Anchor for Aquarium Plants

Aquatic plants float whether or not they are supposed to.

Aquatic plants float whether or not they are supposed to.

Aquarium plants are lighter than water, so they'll rise to the surface as soon as you put them into the tank. Trying to weigh the roots down with substrate will frustrate you. You need an anchor that won't pollute the water. River rocks and fishing line will do it.

Collect a few small, unevenly shaped rocks. Select rocks made of hard minerals like granite, not soft ones like limestone, which would slowly dissolve in the tank and change the chemistry of the water. River rocks are a good choice.

Brush off dirt, if you collected the rocks outside, and rinse them. Sterilize the rocks by boiling them in a glass plan for at least 20 minutes. Allow them to cool.

Tie the thread or fishing line tightly to the rock and use the other end to make a loop around the plant’s stem just above the roots. .

Snip off the loose ends of thread.

Position the plant in the tank and repeat the process for any others.

Items you will need

  • Small rocks
  • Glass pan
  • Thread or nylon fishing line
  • Scissors


  • To ensure that a rock won’t gradually dissolve in your aquarium, drip a tiny bit of white vinegar onto it before boiling. If the vinegar bubbles, don’t use the rock.
  • Once the plant has become well-rooted in the gravel, cut off the fishing line and throw it away. Organic threads such as cotton will slowly rot, although not so fast that they’re likely to pollute the water. Artificial materials, such as nylon, will disintegrate very slowly and probably won’t cause problems. To be on the safe side, however, remove the thread or line once you no longer need it.


  • Never use lead fishing weights as anchors, convenient as they might seem. Lead is a toxic metal and you’ll probably kill your fish.
  • Don’t use metal twist-ties to secure the anchor. These aren’t as toxic as lead, but they will rust or disintegrate and pollute the water. For the same reason, don’t use rocks with metallic veins.

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About the Author

Judith Willson has been writing since 2009, specializing in environmental and scientific topics. She has written content for school websites and worked for a Glasgow newspaper. Willson has a Master of Arts in English from the University of Aberdeen, Scotland.

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