Seven Algae-Eating Fish for Your Pond

In any garden pond, despite intensive care, algae form. To a small extent, they even indicate a functioning ecosystem. In the summer months and when the nutrient content in the pond is high, algae can proliferate. They cloud the water and can cause it to tip over. For the fish, this means a sure death sentence. However, some fish can help you control algae, as they count algae as their primary food.

Natural Algae Control With Algae Eaters

Algae eaters do not form a particular order or group of fish. Algae eaters include fish whose food base is algae. Cleaning your garden pond from annoying algae is simplified with these fish. You will save yourself a lot of work in removing algae, and you will not have to use algae killers. With fish for algae control, you prevent the water from tilting. They contain the water from becoming cloudy or creating a carpet of algae. The water will not start to stink.

If there are many algae in your pond, the oxygen content of the water is reduced. The fish will eat the algae and keep the water clean. You can socialize different types of algae-eating fish. Since they are peaceful fish, they usually get along well.

Even if you keep algae-eating fish in your pond, you should not neglect pond care. You should regularly check the water values.

The Suitable Fish: Now it’s Time to Get to Grips With the Algae

Only a few pond owners know which fish belong to the algae eaters. Perhaps the fish in your pond belongs to the algae eaters. It is not evident whether the fish consume algae for many pond owners.

The seven species of fish presented below are algae eaters.

1. The Grass Carp as a Gentle Giant

The grass carp (Ctenopharyngodon idella) can reach a considerable size of 5 feet (150 centimeters). It is therefore only suitable for large ponds. If you cannot offer the animals enough space in your pond, you should refrain from keeping them. The carp fish is one of the largest pond fish. It can even grow more significant than a koi. The grass carp cleans the bottom of the pond and is voracious. It can eat large amounts of algae.

2. Pennant Carp as a Peaceful Contemporary

The pennant carp (Myxocyprinus asiaticus) is also peaceful and very hungry. It has strongly pronounced fins and a striking striped pattern. It grows nowhere near as significant as the grass carp, with a length of up to 2 feet (60 centimeters). The pennant carp not only eats a lot of algae, but it gets along well with other fish and can therefore be socialized well with them.

3. Silver Carp: Voracious but Elegant

And another colleague from the series of carps! The Silver Carp (Hypophthalmichthys molitrix) is peaceful, like all carp fish, but it can also reach a considerable size of up to one meter. You should also keep the silver carp only if there is enough space in your pond. The silver carp is voracious and can destroy a considerable amount of algae quickly. Silver carp are like suspended algae, but for the most part, they do not manage to keep the pond free of algae despite their hunger and size. In addition, you should add mussels or snails to your pond.

4. Small and Modest: The Gudgeon

Significantly smaller and therefore less voracious than the carp is the gudgeon (Gobio gobio). It only reaches a size of about 6 inches (15 centimeters) and is therefore suitable for smaller ponds for algae control. It is nowhere near as effective as the carp fish, but it mixes well with other algae-fighting fish, such as the golden minnow.

5. A Little Beauty: The Rudd

Surely the pretty rudd (Scardinius erythrophthalmus) could win a prize in a pond fish beauty contest. It can grow up to 16 inches (40 centimeters) long and reach a weight of up to 4 pounds (2 kilograms). The rudd likes to eat algae, but it also feeds on rotting parts of pond plants. The rudd is a valuable helper if your garden pond is heavily infested with algae. It is easily confused with the roach (Rutilus Rutilus). However, the roach does not eat algae. The rudd can be distinguished from the roach by its yellowish to the orange iris.

6. The Inconspicuous Nose

The Nose (Chondrostoma nasus) is also known as the Näsling and is relatively inconspicuous. It can be effective in controlling algae. The nose grows 4 to 10 inches (25 to 40 centimeters) long and is more suitable for larger ponds. It likes deeper water and can be kept in deep streambeds. The nose eats mainly algae adhering to the bottom, stones, and other surfaces. Since it has a rigid jaw, it is good at grazing the algae from these surfaces.

7. The Small Gold Minnow as a Classic

The golden minnow (Pimephales promelas) is a classic in garden ponds and well-suited for algae control. It grows only about ten centimeters long and can be kept even in small ponds. Due to its small size, it is also suitable for keeping in large colonies. You can socialize gold minnows very well with other fish.

Even though algae-eating fish can effectively help you control algae, you should adjust the fish population to the size of your pond. If the fish population is too large, the fish’s excrements can contaminate the pond and encourage algae growth. You should also not take it too well with the feeding and instead dose the food sparingly. Otherwise, the fish may no longer have a natural appetite for the algae.

Mollusks and Crustaceans as an Alternative to Fish

Fish in a pond are not a must. In an ornamental pond with aquatic plants, you can do without fish. You can use mollusks and crustaceans as an alternative instead of fish. Such animals are also suitable if you do not keep peaceful fish but predatory fish in the pond, which are not interested in algae. For algae control, crustaceans or mollusks can be even more effective than fish. You can socialize several species at once to control algae sustainably. In natural ponds, a combination of snails, mussels, and crayfish is suitable.

If you keep all three groups of these animals in your pond, all pond areas will be well covered. Each group prefers a particular pond area. Mussels stick to the pond’s bottom, while snails live in the shore area or on the surface. Crayfish stays indifferent pond areas depending on the species. They can take care of the open water area. Using all these groups of animals, you will save a lot of work in maintaining the pond.

Such algae-eating animals that can be well associated with each other are.

  • Pointed mud snail (Lymnaea stagnalis)
  • Tiny swamp snail (Galba truncatula)
  • Swamp lidded snail (Viviparidae)
  • Posthorn snail (Planorbarius corneus)
  • European freshwater shrimp (Atyaephyra desmaresti)
  • Pond mussel (Anodonta cygnea)

Even more suitable than fish for algae control are the pond mussel, the swamp cover snail, and the European freshwater shrimp. The mussel can filter up to 260 gallons (1,000 liters) of water daily. This filtration makes cleaning much more straightforward. You can also socialize these animals with fish. You should only make sure that the animals do not belong to the food of the fish.

If you decide to use some of the described species of snails, you can improve the water quality within a short time. Mollusks feed not only on algae but also on dead plant parts and other dead materials. They prevent the water from tilting and provide an ecological balance.

What You Should Consider When Buying the Algae Eaters

If you want to equip your pond with fish, mollusks, or crayfish as algae eaters, you should not steal any animals from the wild. Various algae eaters are protected by law (in Germany), as the population has been decimated over time. You should also be aware of the risk that these animals are infected with pathogens and could cause problems in your pond with their diseases.

Buy the animals from a specialized dealer or find out where a pond owner’s swap meets in your area. At the swap meet, you can trade fish and other animals and plants with other pond enthusiasts.

Support With Aquatic Plants

In addition to fish and other animals, the plants need nitrate and phosphate as nutrients. Algae also need these nutrients for them to grow. The aquatic plants deprive the algae of food and ensure that the algae can no longer spread. The plants can prevent the water from tilting. Some plants also provide shade and counteract the growth of algae. Suitable plants include crayfish claw and frogbit.


Several fish are great for algae control in your pond as they eat algae. Which fish you choose depends on the size of your pond. Several carp species are voracious, but they reach considerable size, making them suitable only for large ponds. Better for smaller ponds are golden minnows, gudgeons, or rudd. These fish also mix well with each other. You can also use snails, mussels, and crustaceans as an alternative to fish for algae control.

Florian Egert

I am Florian Egert, the owner of I live with my wife and two children in Germany in a small village in the countryside.

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