Asian Leeches in Shrimp Tank: Stay or Go?

Asian leech (Barbronia weberi) cocoon development (shrimp tank) main

The topic of leeches in shrimp tanks is quite controversial because opinions vary on whether they pose a threat to shrimp. In my opinion, there is a simple explanation for that – the main issue is that aquarists often can’t identify the leech species in their tanks.

One of the most common leeches in the world, the Asian leech (Barbronia weberi), would be an extremely unwelcome guest in a shrimp tank as it is a predatory leech.

In this article, I will delve into what the Asian leech is, its life cycle, how it can get into our tanks, how it reproduces, and much other interesting information based on scientific research and the experiences of aquarists.

Taxonomy of Asian Leeches

Domain: Eukaryota (Organisms with Cells)
Kingdom: Animalia (Animals)
Phylum: Annelida (Segmented Worms)
Class: Clitellata (Clitellates)
Subclass: Hirudinea (Leeches)
Order: Arhynchobdellida (Jawless Leeches)
Family: Salifidae (Freshwater Predacious Leeches)
Genus: Barbronia
Species: B. weberi

This genus currently contains eight species: B. arcana, B. assiuti, B. borealis, B. gwalagwalensis, B. nepalensis, B. rouxi, B. shillongensis, and B. weberi.

Note: Nowadays, the genus Barbronia draws significant scientific interest due to its rapid global expansion facilitated by human introductions. The capability of a single leech to produce hundreds of offspring annually, even without mating, is a key factor here.

Distribution of Asian Leeches

Initially, Barbronia weberi had a native range from Afghanistan and Pakistan to Java, Sumatra, Borneo, India, and Southern China.

In recent years Asian leech has become established on every continent, except Antarctica. It was introduced to South and North America, Australia, New Zealand, and Europe (Italy, England, Hungary, Austria, and Germany).

The aquarium trade is the most probable source of introduction of this species.

Habitat of Asian Leeches

These leeches generally prefer stagnant (ponds, lakes, swamps, etc.) or slow-moving bodies of water and are often associated with aquatic vegetation using plants for the attachment of cocoons.

Description of Asian Leeches

  • Size. These small-sized leeches generally grow up to 1.0 – 1.4 inches (2.5 – 3.5 cm) long with a maximum body width of 0.13 inches (3.3 mm). At the same time, they can stretch their bodies to 2-3 times their original length.
  • Asian Leeches (Barbronia weberi) in Shrimp Tank Stay or Go. description
    photo source

    Shape. The body is elongated, segmented, worm-like, tapering towards the front. This species has tiny bumps covering its body, giving it a rough texture.

  • Sucker. The anterior sucker has a maximum width of 0.035 inches (0.9 mm), while the posterior sucker has a maximum width of 0.079 inches (2.0 mm). The posterior sucker is directed ventrally.
  • Color. They usually have reddish to brownish-yellow coloration while the ventral side is whitish. These leeches exhibit minimal pigmentation.
  • Eyes. Barbronia weberi has 3 pairs of circular eyespots.
  • Reproductive organs. The gonopores are large, well-visible, and separated by 5.5 annuli.

For a detailed description of Barbronia weberi, you can refer to this scientific paper and here.

Life Cycle of Asian Leeches

The life cycle of Asian leeches typically involves several stages:

  1. Egg: Adult leeches lay eggs in a gelatinous cocoon deposited on the plants.
  2. Embryo: The eggs hatch into embryos within the cocoon. The embryos develop and grow inside the cocoon until they are ready to hatch.
  3. Juvenile: After hatching, the young leeches emerge from the cocoon. They are tiny copies of the adults.
  4. Growth and Development: Juvenile leeches prey and feed on organic matter, growing and developing over time. As they feed, they undergo several molts, shedding their outer layer to accommodate their increasing size.
  5. Maturity: As the leeches mature, they reach sexual maturity and become adults. Adults can reproduce and produce eggs, continuing the life cycle.

Lifespan of Asian Leeches

According to the study, the average life span of Barbronia weberi is about 122 days. The maximum lifespan recorded was 216 days, but this can be considered an exception rather than the norm.

Reproduction of Asian Leeches

Barbronia weberi is hermaphrodite species, each individual possessing both male and female reproductive organs and assuming both roles simultaneously during mating.

However, according to the study, it was also found that Asian leeches can reproduce without cross-fertilization as well. Therefore, it only takes one leech in the aquarium for an infestation to occur later on.

Asian leech (Barbronia weberi) cocoon development (shrimp tank)
photo source

Some facts about Asian leeches reproduction:

  1. Barbronia weberi produces cocoons every week for up to three months at which time the adults begin to senesce.
  2. They attach their cocoons to either on aquatic vegetation, rocks, or the sides of aquaria. On the leaves, they are usually attached near the base of the leaf whorls or along the stem making them difficult to see.
  3. Cocoons generally contain 1 to 5 eggs.
  4. Eggs hatch within the cocoon after 2 days and larvae/juveniles remain within the cocoon for 25-30 days.
  5. The fluid inside the cocoons contains all of the nutrients that are required for growth and development as the parent provides no food or care following cocoon production.
  6. After leaving the cocoon the young leeches are 0.2 inches (5 – 6 mm) long.
  7. Emerging young leeches can feed on prey larger than themselves. Most survive to maturity after their first meal, but if they don’t feed within a day, they usually die.
  8. Parents did not interact with cocoons or young after hatching, except for cannibalism when adults ate the young.
  9. Depending on the temperature and food availability, these leeches become adults and reach reproductive maturity within 2-4 months.

Typical Behavior of Asian Leeches

Asian leech (Barbronia weberi) cocoon development (shrimp tank) in substrateAsian leeches typically inhabit substrates where they have access to decomposing organic matter or small organisms, such as worms, which they feed on.

While they can swim using undulating movements through water, it’s not their primary mode of transportation.

They are nocturnal animals. However, their activity patterns can also be influenced by factors such as food availability, environmental conditions, and the presence of predators.

Although leeches may congregate in areas with high food availability or during mating, they are still not considered social animals. They lead solitary lives.

What Do Asian Leeches Eat?

As I mentioned earlier, all leeches of the Family: Salifidae and Genus: Barbronia belong to the category of freshwater predacious leeches.

According to the study, in its natural environment, Barbronia weberi feeds on a range of invertebrate taxa including: oligochaetes (worms), snails, crustaceans, and even insects.

In aquariums their main food will be all kinds of worms, including:

Although adult eeches can go for long periods without food, once they gain access to food, their appetite becomes insatiable. Instances of cannibalism among them are also not uncommon.

Do Asian Leeches Eat Planaria?

A while back, I came across reports from aquarists stating that after the appearance of these leeches, the number of planaria sharply decreased in the tanks.

This suggests that planaria could theoretically also be part of the Asian leeches’ diet. However, this is currently just speculation and requires more evidence.

Related article:

Are Asian Leeches Dangerous to Shrimp, Fish, and Snails?

Shrimp tanks 

No, by no means it is safe to have Asian leeches in shrimp tanks. Period. These leeches are fast enough to catch not only weak but also healthy shrimp. Molting shrimp will be an easy meal for them.

Of course, you can always find information on the Internet where aquarists claim they have never had issues with leeches in their shrimp tanks, and so on.

However, I believe they may be mistaken. They are primarily mistaken about the types of leeches because not all leech species pose a threat to shrimp.

Nevertheless, since identifying leech species requires specialized equipment, I lean toward the position that it’s better to err on the side of caution.

Therefore, if you spot leeches in your aquarium, it’s best to assume the worst and try to remove them immediately.

Snail tanks

Freshwater snails are not the primary food source for this species of leech. However, if they are hungry, there have been cases of them attacking snails as well.

Therefore, I would also exercise caution, especially if you keep decorative snail species which do not have trap doors that would allow them to close their shell when threatened.

Fish tanks

No, Asian leeches cannot harm your fish. On the contrary, many fish species will eat them. The leech’s movements trigger their hunting instinct.

How Do Asian Leeches Get in Our Tanks?

Actually, it is very easy to accidentally introduce Asian leeches into your tank.

These leeches are often associated with aquatic vegetation (such as the waterweeds Hydrilla verticillata, Elodea sp., etc.). Thus, their eggs will often hitchhike on aquatic plants. In most cases, they are just too small to see and a few weeks later, you start to see them in the tank.

Sometimes they can come even with new live food, particularly with worms.

Related article:

How Do I Get Rid of Asian Leeches In My Aquarium?

Right from the beginning, I need to say that unless it is a bare-bottom tank, it is almost impossible to get rid of them.

Yes, you have heard me right.

I have checked lots and lots of forums, I have asked people about this problem and I have also tried some of these methods myself, such as using salt, dog dewormer, No-planaria products, etc.

Unfortunately, none of the methods I tried seemed to work for me.

I have heard that a very high concentration of these products might be effective, but in my situation, it wasn’t a feasible option because it could also harm the shrimp. Using elevated concentrations of copper is also not an option.

Later, I read in one study that Barbronia weberi doesn’t like too warm water (exceeding 86°F or 30°C) I haven’t had the opportunity to test this theory yet.

Copper

There is no need to explain, that Copper is very dangerous in fish and shrimp keeping. All crustaceans, like dwarf shrimp, crabs, crayfish are especially sensitive to it.

  • Buy a copper test kit.
  • Lower the water volume as much as you can. The more water you can drain out of the tank, the more effective the treatment can be.
  • Add Copper sulfate. The concentration should be at least 1.5 – 2 mg/l (or 5 – 2 ppm).
  • Leave the tank for 3 days.
  • Fill the tank and do a large water change.
  • Fill the tank again and test the copper level.
  • You need to remove copper before adding fish or shrimp back.

The downside of this method is that:

  • Any residual traces of copper can still kill the dwarf shrimp when you decide to move them back.

Related article:

The Nuclear Option

  • Evacuate all your shrimp, and snails into another bare bottom tank (quarantine tank).
  • Visually check that no leeches were transferred.
  • Do a tear down.
  • Scrub and clean your tanks, decorations, and driftwood with Hydrogen peroxide.
  • Leave them in the sun to dry for a few days.
  • Throw away the sponge (Replace the filter media).
  • Quarantine plants.
  • Ideally, you should never re-use substrates from an infected tank. If you still think of using it – boil it or pour boiling water on the substrate straight from a kettle. Stir the substrate to kill everything in it. To make sure, add bleach for 5-10 min.

Introducing Leech Eating Fish

There are many types of fish that will eat leeches.

Cichlids (like Julidochromis, Oscar, Red Devils), Loaches (like Clown loaches, Zebra Botia, Macracantha Botia loaches), Bettas, Mollies, Tetras, Pea puffers, etc. will often go straight after them.

The downside of this method is that:

  • You have to introduce a new fish to your aquarium that you may not want in there. For example, even a small fish like Cardinal tetras or Guppies is not safe for shrimp tanks.
  • In large tanks, once you have leeches established, even fish might not be able to wipe them out completely. At least it will take them a lot of time. They are always hiding in the substrate. You will not see them in the daytime, but they will be there.

Manual Removal Trap

Use the tweezers to grasp the leech by its body.

How to Prevent Asian Leech Infestation?

The best way to keep Asian leeches (basically, any pests and/or parasites) out of your tanks is to head off the problem before it takes hold.

Therefore, always quarantine everything!

Treat everything as if it is heavily infected. I seriously mean it.

Plants, rocks, driftwood, decorations, etc. – anything coming from another source that may have been in contact with any biological material.

If you practice an extended quarantine you will notice that there are leeches and can deal with them.

Related articles:  

In Conclusion

The Asian leech (Barbronia weberi) is typically a freshwater predator of invertebrates.

In aquariums, they typically arrive on plants, and even one individual is enough for them to infest within months.

Unfortunately, it is really hard to get rid of them because this invasive species of leeches is highly resilient, and practically anything that can kill them will also harm your shrimp.

That’s why the primary method of combating them is through preventive measures. Avoid adding untreated or unquarantined plants to your aquarium.

References:

  1. Genoni, Pietro, and Andrea Fazzone. “Barbronia weberi (R. Blanchard, 1897)(Hirudinea: Salifidae), an Asian leech species new to Italy.” Aquatic Invasions3, no. 1 (2008): 77-79.
  2. Govedich, Fredric R., Bonnie A. Bain, Martin Burd, and Ronald W. Davies. “Reproductive biology of the invasive Asian freshwater leech Barbronia weberi (Blanchard, 1897).” Hydrobiologia510 (2003): 125-129.
  3. Bolotov, Ivan N., Tatyana A. Eliseeva, Alexander V. Kondakov, Mikhail Y. Gofarov, Olga V. Aksenova, Yulia V. Bespalaya, Alexander V. Kropotin, Oksana V. Travina, and Maxim V. Vinarski. “Barbronia borealis sp. nov., the first salifid leech discovered in Russia, with a global checklist of this genus.” Ecologica Montenegrina63 (2023): 24-38.
  4. Ludányi, Mercedesz, Daniel Balla, Zoltan Mueller, and Bela Kiss. “The first occurrence of Barbronia weberi (Blanchard, 1897)(Hirudinea: Arhynchobdellida: Erpobdelliformes: Salifidae) in Hungary.” BioInvasions Records8, no. 3 (2019): 633-639.
  5. Bandyopadhyay, P. K., and C. K. Mandal. “On the Occurrence of Five Leeches Barbronia weberi, Glossiphonia annandalei, Glossiphonia heteroclita, Glossiphonia reticulata and Placobdella undulata in West Bengal, India.” Records of the Zoological Survey of India(2005): 93-101.
  6. Chandra, Mahesh (1991). The Leeches of India: A Handbook. Zoological Survey of India. p. 69.
  7. Mason, Julia. “Studies on the freshwater and terrestrial leeches of New Zealand. 2. Orders Gnathobdelliformes and Pharyngobdelliformes.” Journal of the Royal Society of New Zealand6, no. 3 (1976): 255-276.
  8. Iwama, Rafael Eiji, and Eliane Pintor Arruda. “Leeches of the genus Helobdella (Clitellata: Hirudinida) from São Paulo, Brazil with descriptions of two new species using micro-computed tomography and a new record of Barbronia weberi (Blanchard 1897).” Zootaxa 4144, no. 3 (2016): 411-429.

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