What Are Water Mites? Are They Harmful?

Sharing is caring!

Water mites in your fish tank can be a worrying concern. Or it may be nothing serious at all.

It depends on the specific variety of the mite you’re dealing with.

One of the first things you should know about these little bugs is that they exist naturally in the aquatic ecosystem.

But no aquarist wants to wake up to the sight of tiny bugs inside their tanks every morning.

water mites in fish tank

And that’s exactly why you may want to eliminate them from your aquarium.

This guide will explain the presence of water mites inside the tank, including if they will harm your fish.

Let’s start with an obvious question; what are these tiny mites inside the tank?

What are Water Mites?

Water mites are one of the many groups of benthic arthropods and belong to several families. Scientists have described up to 5000 species of these mites, occupying benthic habitats like lakes, springs, and riffles.

Water mites live naturally in the aquatic environment. But sometimes find their way into closed aquariums and hide in the substrate.

Juvenile species are easily noticed by the naked eye as they swim freely inside the tank. But this changes in adulthood, with the mites hiding deep in the substrate.

Water mites belong to the class Arachnida and resemble the common spiders in many ways. And some of the most common varieties include the following;

  • Daphnia
  • Ostracods
  • Copepods
  • Amphipods

How Water Mites Get into Aquariums

Water mites may get into your aquarium via the substrate or other tank decorations, including sand, aquarium plants, and live rock.

While inside the tank, they aren’t easily noticed by the naked eye.

However, their population increases rapidly inside the tank. And it won’t be long before you spot them in the juvenile or larval stage.

Also, excess food and warm temperature increase the mites’ population inside the tank.

Some mite varieties, like copepods, thrive in fresh and saltwater conditions, while amphipods flourish in saltwater environments alone.

Water Mites Aren’t as Harmful, or At Least Most of Them

Water mites aren’t as dangerous as many aquarists assume. And there’s no need to panic when you spot them inside the tank.

You see, these little bugs exist in aquatic habitats as an important part of the ecosystem. And a few names, like daphnia, are an important food source for most aquarium fish.

But trouble begins when the mite’s population spiral out of control.

In that case, you may notice a range of problems, such as a change in water pH, parasitic infections, and reduced oxygen levels inside the tank.

What’s more, the parasitic mites may cause endless irritation to your beloved aquarium fish.

Gill mite-infected fish will be lethargic, develop respiratory issues, and spend much of their time near the water surface.

As you may probably know, a large population of mites also lowers the tank’s aesthetics.

This is what makes them bothersome in the aquarium community. And it’s no surprise some aquarists may want to eliminate them.

Ultimately, it depends on the type of mites inside the tank and how they affect your fish.

Identifying the Water Mites

The truth is, you will struggle to spot water mites inside the tank.

And when you do, it will most likely indicate a spiraling population out of control or a group of water mites in their larval stage.

Water mites resemble fat aquatic spiders with small heads, round bodies, and eight legs. 

Some varieties take on a characteristic shrimp-like appearance or floating crystals. 

You can spot them as small, black, or white spider-like creatures inside the tank. But sometimes, you will see them floating all over the place or on the aquarium plants and other decorations.

Will Water Mites Kill Your Fish?

Not all water mites are harmful to your fish.

But when they invade your aquarium, some fish may show signs of infection, such as lethargy, restlessness, and reduced appetite.

Other symptoms include cloudy eyes, damaged fins, and skin lesions.

Also, some aquarists have reported cases of clogged filters and siphons from the presence of water mites inside the tank.

While water mites won’t affect your aquarium fish directly, they can reduce their quality of life in captivity. This reduces the fish’s lifespan inside the tank.

Getting Rid of the Water Mites

Many aquarists won’t bother removing water mites from their tanks because they aren’t dangerous.

However, an increasing population could indicate potential problems with your tank.

And for that reason, you may want to get rid of them from the tank altogether.

Below are the five best tips for eliminating these little critters if they become a nuisance to your fish;

1. Do Nothing


You don’t have to bother when the water mites don’t trouble your fish.

This strategy requires constant monitoring to ensure the mites’ population doesn’t go out of control. So, keep a keen eye on them from time to time to assess the risk of infections.

Usually, the adult bugs will stay in the substrate and won’t get in your fish’s way if they have enough food.

2. Introduce Pod Eaters to the Tank

There’s a long list of aquarium fish that will happily feed on the little critters inside your tank, including;

  • Angelfish
  • Firefish
  • Shrimp
  • Crabs
  • Mandarin Fish

It’s important to note that most of the names on the list are saltwater species. And they will thrive under brackish conditions when you keep them at home.

Also, remember these pod eaters require a huge amount of food to survive in captivity. And you may want to supplement their diet with high-quality fish foods even when you bring them primarily to eliminate the bugs.

Alternatively, you can harvest the water mites in plenty to ensure your pod lovers never run out of food in captivity.

3. Modify the Tank

Water mites can be a menace inside the tank, depending on the variety you’re dealing with. Some increase stress levels inside the tank, threatening your fish’s life at the end of the day.

For that reason, you can modify the tank to help you eliminate the bugs.

A significant step here would be using a canister filter with the right features to filter out the bugs immediately.

4. Deep Clean and Maintain Your Aquarium

Of course, general tank cleanliness is the best strategy for solving many problems affecting your fish. And eliminating bugs is just one of those.

Some people clean their tanks once a week. Others do it once a month.

But the real answer depends on many factors.

The overall assumption is that the frequency of cleaning your tank depends on the number of fish you keep. But you can work with a biweekly schedule if you spot water mites inside the aquarium.

Deep cleaning should involve siphoning the substrate, wiping the glass, and checking the water filter is functioning smoothly.

Don’t forget to check the water quality, prune the aquarium plants, and refill the tank with clean water.

5. Check the Water Parameters

Water mites thrive under reduced tank water quality. And you will want to maintain stable water parameters to control their population at home.

As part of the cleaning routine, assess the water parameters, including the pH, water temperature, and ammonia and nitrate levels.

Other helpful tips include performing frequent water changes and maintaining a stable and acceptable water column.

Preventing the Water Mites

As we’ve mentioned, water mites are difficult to spot with the naked eye. And eliminating them will be even harder.

Therefore, prevention should be your priority, no matter the type of bugs inside the aquarium.

Start by quarantining new fish species for at least 7 days before introducing them to the tank.

This will help you monitor their health and prevent the risk of disease transmission.

Deep cleaning is another effective strategy for keeping water mites at bay. And while doing so, don’t forget to perform partial water changes from time to time to control the algal and bacterial growth.

Eliminating all the bugs from your tank may be impossible. Thus, give it your best shot but don’t feel bad when you spot some leftover critters inside the tank.

Treating Your Fish for Parasitic Infections

You don’t have to panic if you spot water mites inside the tank. But in some cases, the parasitic mites will have done significant damage by the time you notice their presence.

This is where it becomes necessary to treat your fish for parasitic infections.

Start by cleaning your tank. Then, quarantine the infected fish if the symptoms persist before getting the right medications to manage the condition.

Treating your fish with medicinal tablets may continue for many days, depending on the severity of the infection.

And if the disease symptoms still don’t go away, seek expert help from your local veterinarian.

Also Read:

Final Thoughts

In conclusion, tiny bugs inside the tank aren’t as harmful as many people assume. But what everybody knows for sure is that they can lower the tank’s visual appeal.

And in the worst-case scenario, some varieties can irritate the fish’s body, becoming a nuisance inside the tank.

In that case, you can use one of the above methods to eliminate them from the tank.

Ultimately, deciding to get rid of these little critters depends on the type of bugs inside the tank and your preferences.

Hopefully, this guide will help you create a beautiful aquarium as the center of attraction at home.

Sharing is caring!

Leave a Comment