Skip to main content

PawTracks may earn a commission when you buy through links on our site.

Leeches in your aquarium are gross! Here’s how to get rid of them

Does the mere thought of leeches make you cringe? If yes, you’ve got plenty of company among aquarium hobbyists who freak out if they see these creepy parasites attached to fish in their tanks. Luckily, according to aquatic specialists, leeches aren’t a common intruder in tanks with captive-bred fish.

What exactly are leeches?

Leeches are annelid worms closely related to earthworms. They can be white, gray, or brown. While most live in freshwater, a few species can be found in saltwater. Aquarium leeches mostly hide in the substrate or cling to stones or plants. They typically feed at night, so you’ll likely not see them during the day.

Image used with permission by copyright holder

Why are there leeches in my fish tank?

There are several ways that leeches can get into your fish tank.

  • New fish or plants introduced to your tank can be hosts to leech eggs that will then hatch out in the tank
  • Using pre-owned aquarium equipment that’s hosting leech eggs
  • Leeches can be present in live food caught from leech-infested water

Are leeches bad for my fish?

Leeches are parasitic bloodsuckers that will attach themselves to the side of fish or the inside of their mouths or gills. According to Encyclopaedia Britannica, leeches have three jaws set with sharp teeth that make a Y-shaped incision when they bite into flesh. The leech’s saliva contains substances that anesthetize the wound area, dilate the blood vessels to increase blood flow, and prevent the blood from clotting. Experts at PetMD say that symptoms a fish might be infected with leeches include:

  • Lethargy due to anemia
  • Pale gills
  • Redness surrounding the affected area
  • Fish may rub against objects in an attempt to remove the leeches

Small leeches aren’t easy to spot on fish according to aquatic veterinarian Jessie Sanders in an article published by The Spruce Pets.  She advises hobbyists to pay attention to any raised, black lines on fish. This may be a normal coloration or the result of a wound but could also be a tiny leech. When in doubt, Sanders recommends having a fish veterinarian take a look.

How do I get rid of leeches in my aquarium?

Here are a few ways to help rid your aquarium of leeches.

Manually removing

If you notice a leech on one of your fish, Sanders recommends removing it as soon as possible with tweezers. If you’re not confident about doing this, you should reach out to a veterinarian for help.  According to Sanders, a fish veterinarian will safely capture and sedate your fish for easy leech removal. The vet will also examine the sedated fish for additional leeches that may be hiding in cavities.

Leech traps

There are a variety of leech traps on the market for aquariums. For example, the Fantastic_008 Leech Trap has a 4-star rating on Amazon. One happy customer reports that she baited the trap in her 10-gallon tank with Hikari carnivore pellets and attracted more than a dozen leeches within half an hour.

Siphoning the leeches

Depending on the type of leeches in your tank, vacuuming the gravel may help remove them.

Discussions about leeches on fishkeeping forums recommend different solutions for ridding the tank of these parasites including using salt, copper mixed chemicals, and bleach. It’s always safest to reach out to a veterinarian for advice before adding any chemicals to your fish tank. Depending on the product, it could negatively impact the fish or invertebrates in your tank.


Finally, nobody wants to see leeches in their aquarium. Prevention is your best line of defense. Sticking to a regular maintenance schedule will help keep the aquarium clean. Also, quarantining any new fish or plants will allow you to monitor them for problems before introducing them to your tank. Going the extra mile will give you peace of mind knowing you’ve done your best to keep your fish safe and healthy.

Editors' Recommendations

Vera Lawlor
Vera was the pet columnist for 201 Family magazine and has contributed pet and animal welfare articles to Bone-A-Fide Mutts…
How to clear cloudy aquarium water in a few easy steps and make your fish happy
When your aquarium water is cloudy, you'll have to do some sleuthing to find the cause
Hand cleaning tank with sponge

No matter how talented an aquarist or fish parent you are, you'll probably run into cloudy aquarium water at some point. Maybe your filter breaks unexpectedly or one of your fish has tummy problems, and you wind up with a tank so murky you can't see through it.

If you walk in to feed your fish and stumble on cloudy aquarium water, don't panic. While a good tank cleaning will probably be necessary, it's even more important to discover the underlying problem. We're here to show you how to clear cloudy aquarium water and keep your fish safe from filth.

Read more
Add rainbowfish to your tank – these beauties will brighten up any aquarium
There are a few things you need to know before you get a rainbowfish
A colorful rainbowfish swims in front of plants in an aquarium

You might know of rainbowfish from the beloved children's book, but these are real animals that you can keep in your own home. As the name suggests, this group of swimmers is well regarded for being beautiful to behold. Many also get along nicely with other fish and can be handled by beginners. This is what you need to know before bringing home a rainbowfish.
What are rainbow fish?
It's a bit of a catch-all term because there are at least 50 species that all fall under the rainbowfish umbrella. Some work better as pets than others, and you'll probably be looking at boesemani rainbowfish, turquoise rainbowfish, featherfin rainbowfish, or red neon rainbowfish. If you're adding to an existing tank, research carefully to ensure you only get ones that will make friends with your current animals.
What conditions do they need to live in?
These are all freshwater fish, but their exact temperature and pH balance needs vary depending on which species you bring home. You can use your existing tank specs to narrow it down or do the opposite — pick the prettiest fish and then build your ecosystem around it. One thing to note right away is that you shouldn't keep males together and no rainbowfish wants to live on its own because they like to school. Consider keeping a group of six females if you want to prevent expansion.

Why should you add them to your tank?
Here are four excellent reasons to keep rainbowfish as pets.
They look beautiful
You can find just about any gradient you want in a rainbowfish. Some incorporate many colors, more like a traditional rainbow, while others skew toward blue, such as the turquoise rainbowfish, or red, such as the aptly named red rainbowfish.
They get along with other fish
While you want them to have friends of their own species, they'll also do great with others. Female rainbowfish can sometimes live with female bettas if you want to create a color explosion. Otherwise consider catfish, gouramis, and loaches as tank mates.
They're good beginner fish
The care level of most rainbowfish sits at about the same as a neon tetra (in fact, they can live together). Make sure your tank stays clean and that you change and test the water frequently, but they don't have any specialty needs.
They live a long time
Many tank dwellers have short life spans, and rainbowfish won't be any different if not properly cared for. However, boesemani rainbowfish, in the right environment, regularly make it to 5 years and sometimes even t10 years!

Read more
Are female betta fish worth it? Here’s why you should consider getting one of these pretty fish
Unlike males, female betta fish can live together, and get along with other fish, too
A blue female betta in a tank

Betta fish (also known as Siamese fighting fish) rocketed to fame and took a spot as one of our favorite swimming pets for their beautiful color and elegant fins. They, too, are recognized for being aggressive toward each other and will even flare (a display) to you, their owner. However, many of those characteristics only apply to the males of the species, whereas the female versions look and act a little differently. Here's why you should consider bringing one of these lady bettas home.

What are betta fish?
These underwater beauties come from Thailand and live in rice paddies in the wild. It's a myth that they only need a small tank, but bettas often do make great solitary pets that can thrive in an aquarium by themselves. They can also live with many other fish, just not other bettas. One fun thing about these swimmers is that they learn to recognize their owners and will get excited when you come to feed them every night.
How do female bettas differ from males?
You probably know that you can't keep male bettas with others of their kind, as they will fight males and sometimes aggressively mate with females (we recommend only experts breed them). Female bettas won't likely be building any bubble nests though, as that's a job for the males.

Read more