List Of 6 Plants That Can Poison Fish You Didn’t Know!

You might be wondering about the plants that can poison fish. This list contains the following plants:

  • Blue-Green Algae
  • Fagaceae Quercus
  • Yew
  • Cherry Trees
  • Jasmine
  • Tiger Lily

Plants produce toxins so that they can protect themselves from being eaten by other organisms. That includes fish too. Historically, the fish toxin has been used by hunters and fishermen to stun fish so that they are easy to collect. 

Tribal people would make the fish-stupefying toxin from various plants and then use it to catch them in the sea or rivers.

These toxins would not kill the fish like a chemical toxin but would instead render them motionless. The fish would then float to the surface, and the hunter would easily capture them.

This practice was common among Australian Aborigines and California Indians; people still use it in some parts of the world.

There are also plants that, if ingested by the fish, will have fatal results. Some plants may have only toxic leaves, and others may have toxic compounds in roots.

Additionally, some plants are also poisonous overall. Some plants are only toxic to fish, also known as ichthyotoxic. 

If these kinds of plants are near to your fish pond or your fish, they may cause them to become sick, disrupt their metabolism, and, in extreme cases, they may even die.

We have listed some plants that are toxic to fish below.

Blue-Green Algae

plants that can poison fish
armennano | Pixabay

Although it is not actually a plant, it still survives by photosynthesis. Mentioning it is crucial because it is potentially quite harmful to plants. It has a blue-green appearance and is bacteria, not algae, although it looks like one when it blooms out. While its presence is natural and even beneficial in some cases, their bloom may cause muscle degeneration, oxygen depletion, and damage to the internal organs of fish. It is easier to monitor in small fish enclosures.

Fagaceae Quercus

plants that can poison fish
Hans | Pixabay

Fagaceae Quercus or oak occurs naturally in many parts of the world. Some oak species produce toxins called tannins. They don’t necessarily cause death but can create digestion issues. If they fall in the water where your fish is and is consumed by it, they will be prone to sickness. Even if the fish doesn’t consume it, the build-up of these leaves and acorns in the water can change water quality upon decomposition.


plants that can poison fish
Alexas_Fotos | Pixabay

Yew or Taxus species grow into shrubs or can be trained to grow into mature trees. They have fragrant needles and large swooping branches. The needles and seeds of the plants of these trees are toxic to fish as they have taxine alkaloids.

Cherry Trees

plants that can poison fish
shell_ghostcage | Pixabay

Cherry trees are beautiful and fragrant with their beautiful blossom. Most cherry species are toxic to fish, though. All parts of a cherry tree are toxic to fish, particularly the seeds. They contain hydrocyanic acid, which is also known as prussic acid. It can even cause the fish to die. It blocks the ability of tissues to use oxygen, which causes asphyxiation in fish.


plants that can poison fish
Capri23auto | Pixabay

This beautiful shrub plant bears pretty and fragrant flowers. Some of its species are also evergreen. These plants have toxins in their berries, which includes glycoside and hepatotoxin. They cause disruption of the nervous system in fish.

Tiger Lily

plants that can poison fish tank
Lancier | Pixabay

They are pretty and straightforward to grow. However, you should avoid them because they have lycorine alkaloids in all parts. It causes nausea and convulsions. It can also disrupt protein synthesis in fish.

Plants That Can Poison Fish: FAQ

Find related questions to plants and fish. If you can’t find the question you’re looking for, ask below!

What are the plants safe for fish ponds?

In one of our recent articles about plants safe for a fish pond, the plants listed are water hyacinth, water smartweed, water lotus, water lily, and horsetail. Try not to add too many plants at once because it can cause harm to your goldfish by reducing the level of oxygen.

Are ferns poisonous to fish?

Ferns aren’t poisonous to fish but if you add too many, it can cause more harm than good. The reason for this is because the plants can rot, which releases unnecessary wastes.

Are pine needles poisonous to fish?

Pine needles may appear like a great addition to add in with your fish because it can make it look aesthetically pleasing. The truth is – they are harmful and poisonous to your tank.

From VivariumTips, 


Plants are a beautiful creation of nature, but they can also be dangerous. Some plants only cause minor problems among fish when ingested, but others can cause them to die. If you are thinking about introducing plants near your fish enclosure, be wary of the ones we mentioned above. 

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