List of Aquatic Herbicides Safe For Fish

You may want to know which products can pose a danger to your fish if administered to them.

We must get to know the aquatic herbicides safe for fish to avoid using herbicides that will contaminate, or kill the fish in the water body.

Aquatic herbicides can be administered directly onto the floating aquatic plants or applied into the water. They are either in liquid or pellet form and can be of different types; systemic, contact, selective, or non-selective types.

Systemic herbicides can kill the whole plant whether each part came in direct contact with the aquatic herbicide or not. The herbicide is transported through the plant.

Foliar application transports the herbicide down to the roots while soil application transports it up to the leaves killing the entire plant. Contact herbicides have a regenerative quality.

They cause the parts of the plant that came in direct contact with the herbicide to die. This way, the roots remain alive and the plant can regrow.

Non-selective herbicides affect all types of plants that they come in contact with while selective herbicides affect only specific types of plants when they are applied and leave others unharmed.

Some herbicides are safe to use on land but not in the water with fish. This is the reason for the emphasis on aquatic herbicides safe for fish’. Others are safe to use in water with fish but in considerable amounts only.

If the wrong herbicide is used or if there is an improperly performed treatment, it could lead to low oxygen in the water. This is a result of too many plants dying and decomposing within a short period and utilizing the available oxygen in the water.

With this occurrence, there’s a high possibility of fish killing. The wrong application can also result in disease in the fish which together with overfishing will contribute to a drastic reduction of the fish population, or make them harmful for consumption as food.

The fact is that aquatic plants are essential to the aquatic environment. They play important roles in the environment and their unchecked growth also causes damage to aquatic habitats. Some of the values of aquatic plants are:

  • Aquatic microscopic plants such as algae are basic components of the food chain. For instance, algae supply nutrients for fish.
  • During photosynthesis, all plants produce oxygen which is a good thing for the fish.
  • Larger aquatic plants also provide a habitat for fish in lakes and other water bodies.
  • Algae reduce toxicity in the water.

These water bodies can be so rich in nutrients that they make the growth of these plants or weeds in the water to be alarming. Therefore, the rate at which these plants grow hurts the water body and the aquatic habitat.

Dangers of Aquatic Plants to Fish

Some of the dangers of unchecked aquatic plants to fish are:

  • Reduction in the Growth of Fishes
  • Change in Water Properties

1. Reduction in the Growth of Fishes

High densities of aquatic plants can reduce the growth of some fishes. This is because forage fish can be hidden from predator fish as a result of the high density of aquatic plants.

The removal of these plants exposes forage fish to predator fish species such as largemouth bass, black and white crappie, and bluegill.

2. Change in Water Properties

Aquatic plants can change water temperatures and affect the available oxygen, affecting their survival and growth. The dense growth of stems and leaves can interfere with water circulation and surface exchange of atmospheric oxygen, resulting in low dissolved oxygen.

Therefore, fishes that need high oxygen such as larger fishes are fewer. However, smaller fish can be found in greater quantities because they need a lesser amount of oxygen.

The good thing is that there are aquatic herbicides that can destroy or stop the fast growth of these plants and they are safe for fish.

So, in this article, we are looking at the list of aquatic herbicides safe for fish.

These aquatic herbicides safe for fish are potent for aquatic weed management, such as pond algae, pond weeds, and lake weeds.

Also, these aquatic herbicides safe for fish are functional aquatic weed killers for the entire water bodies or part of it, and they can also properly control aquatic weeds in dock or swim areas.

What are Aquatic Herbicides?

Aquatic herbicides are chemicals used to get rid of unwanted aquatic plants or stop their growth. total or unselective aquatic herbicides and selective aquatic herbicides.

How to Get Rid of Pond Weeds Using Aquatic Herbicides 

When you want to get rid of pond weeds, the first thing is to carefully identify the unwanted species that are present in the pond, and properly take note of their physical attribute.

This process of identifying the plants seems to be tedious most time as you have to go through some processes like dichotomous keys, stereoscope, and lab tests. When you identify the unwanted species, it will then enable you to know the kind of aquatic herbicide to use that will be safe for fish.

You can also control pond organisms via the application of nutrient reduction products like Alum, Phoslock, or Biochar—These products naturally remove pond nutrients and so prevent the growth of undesired aquatic plants. Or apply bio-control measures such as stocking triploid grass carp (a type of vegetarian fish).

For some critical cases, you may use hydro-raking or dredging.

You also may require the use of a new “reduced risk” herbicide alternative called ProcellaCOR, which is produced for just targeted species.

It will be good for you to work with a professional who knows these options and how to apply them in the most productive way to guarantee safety. And your region’s regulations can act as guides too.

Among all these methods, aquatic herbicide is the most popular. But in using it, aquatic herbicides safe for fish must be considered in water bodies with fish.

Let’s now proceed to the list of aquatic herbicides safe for fish.

List of Aquatic Herbicides Safe for Fish

  • Fluoridone
  • Flumioxazin
  • Diquat
  • Glyphosate
  • 2,4-D

1. Fluridone

list of aquatic herbicides safe for fish
fluridone (source: Alligare)

Fluridone is an aquatic herbicide safe for fish. In 1986 it was originally registered with the EPA. The ingredient effective is 1-methyl-3-phenyl-5-3-(trifluoromethyl)phenyl|-41H|-pyridine.
Is an aquatic herbicide that acts systematically to eradicate unwanted plants in the water body.

Fluridone is not used at a high concentration but it is used at very low concentrations.

A term you can use with the herbicide is ‘mild’. It takes about one to three months to eliminate the weed in the water body and if the fluridone is removed before the plants are destroyed, they will still be able to produce chlorophyll and grow back.

The water can be used for irrigation or drinking. As a camaraderie of other aquatic herbicides safe for fish, fluridone is harmless to fish.

2. Flumioxazin

Flumioxazin is a wide-ranging contact aquatic herbicide safe for fish. It works by hindering the plants’ production of chlorophyll. Plants that are treated will respond to treatment immediately and fast decay.

list of aquatic herbicides safe for fish
Flumioxazin (source: Agriculture XPRT)
For thick vegetation, treatment will split for two weeks to prevent fish suffocation from low oxygen due to decomposing plants in the water.
It acts fast and its function is to control unwanted plants in the waterbody.
Flumioxazin needs to be applied to seedlings early in the beginning before they start growing. It should not be applied in very hard-water lakes (pH over 8.5).
The application should be done early morning which increases usefulness, especially in hard-water lakes. Flumioxazin should be used to treat water bodies with an outlet or in moving waters such as rivers or streams. Flumioxazin is decomposed quickly by water and microorganisms.
Flumioxazin breaks down into two compounds known as APF (6-aminoleaching and would -7-fluoro-4-(2 propynyl)-1,4,-benzoxazin-3(2H)-one) and THPA (3,4,5,6-tetrahydro phthalic acid). Flumioxazin does not persist in the water, soil, or environment.
As one of the reliable aquatic herbicides safe for fish, when flumioxazin is applied, the water is still safe for swimming, eating fish, or pet/livestock, and even drinking water. However, there is a five-day restriction on irrigation.

3. Diquat

List of aquatic herbicides safe for fish
Diquat (source: Awiner)

Diquat, or diquat dibromide, is the general name of the chemical 6,7-dihydrodipyrido (1,2-a:2′,1′-c) pyrazinediium dibromide. Diquat is an aquatic herbicide safe for fish and does not have any apparent short-term effects on most of the aquatic organisms that have been tested at the rate of application.

To date, they have not discovered any notable short or long-term impacts on fish and other aquatic organisms in lakes or ponds that are being treated with diquat.

Bioconcentration is not expected to be a concern with diquat because bioconcentration factors that were measured for diquat in fish tissues are low.

Diquat is a fast-acting herbicide that works by obstructing cell membranes and constraining photosynthesis. It is a non-exclusive herbicide and will eliminate a vast species of plants on contact.

It does not have contact with all the plants when it is applied, so it only kills parts of the plants that it contacts. plants die a week after the treatment has been applied treatment, and plants will die within a week.

Diquat will not be active in lakes or ponds with muddy water or where plants are surrounded by mud because it is very attracted to mud and clay particles in the water.

During treatment, the bottom sediments should not disrupt. Only partial treatments of ponds should be carried out (1/2 to 1/3 of the water body). If the whole pond were to be treated, the decaying vegetation may result in very low oxygen levels in the water.

This can be deadly to the fish and other aquatic habitats.  Untreated areas can be treated within 10-14 days after the first treatment has been carried out.

Maybe what shot diquat to the list of aquatic herbicides safe for fish is that there are no limitations on swimming and the fish from water bodies treated with diquat are consumable. Notable, isn’t it?

4. Glyphosate

list of acquatic herbcides afe for fish
glyphosate (source: derbauco s.a.)

Glyphosate is a well-used herbicide that is used in both aquatic and terrestrial sites. is also an aquatic herbicide safe for fish.

Pure glyphosate is less destructive to fish and other aquatic habitats. Still, some of the products that contain glyphosate may be harmful due to the addition of other ingredients in them. Glyphosate affects fish and other organisms incidentally because killing the plants changes the animals’ habitat.

When glyphosate is used correctly according to the label, it won’t cause harm to aquatic animals as it is not consumed by fish, birds, insects, amphibians, or reptiles. Glyphosate is broken down by microorganism that is organically present in the water making it to the list of aquatic herbicides safe for fish.

According to a laboratory test conducted with a herbicide, the manufacturer proves that glyphosate is toxic to carp, bluegills, trout, and water fleas (Daphniaspp.) only when applied beyond the application rates.

Glyphosate is a systemic herbicide, when applied it goes to all plant issues and works by obstructing an important enzyme needed for multiple plant processes, including growth. Glyphosate is active only on plants that grow above the water. It will not be effective on underwater plants.

5. 2,4-D

2,4-D is surely one of many aquatic herbicides safe for fish. It is on a granular or liquid formulation. Granular 2,4-D manages submerged weeds and emergent weeds such as water lilies (Nymphaea spp). this is an aquatic herbicide safe for fish.

list of aquatic herbicides safe for fish
2,4-D (source: Ubuy)

The harmfulness of aquatic 2,4-D products changes depending on the type of formulation. The formulation could be either amine or an ester 2,4-D.

The ester formulations are harmful to fish and some important invertebrates such as water fleas (Daphnia) and midges at the rate of application.

2,4-D is available in both ester and amine formulations. Amine formulations are a little bit better for aquatic applications because they are less harmful to fish, and the granular ester form is also safe to use.

2,4-D is, without doubt, one of the aquatic herbicides safe for fish; the record has shown that 2,4-D does not accumulate at a notable level in the bodies of fish that have been tested.

Though some fish exposed to 2,4-D will take up some of the chemicals, the small amounts that pilled up are killed after exposure to 2,4-D desist.


In this article, we addressed the list of aquatic herbicides safe for fish. Aquatic plants are useful but when untamed, can be dangerous to aquatic life. Among the aquatic herbicides safe for fish that can be used are diquat, flumioxazin, 2,4-D, fluridone, and glyphosate.

These herbicides are so safe that the application of some of them in recommended proportions doesn’t make the water unsafe for drinking, the fish can still be consumed and they can be used for irrigation plants, all within specified periods.

 List Of Aquatic Herbicides Safe For Fish – FAQ

What type of herbicides are not safe for fish

Organophosphate herbicides Glyphosate-based herbicides Roundup herbicides


Precious Okafor is a digital marketer and online entrepreneur that got into the online space in 2017 and since then have developed skills in content creation, copywriting and online marketing. He is also a Green activist and hence his role in publishing articles for EnvironmentGo

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