Micro-wildlife Active day and night

Difflugia

Cylindrifflugia acuminata

iNaturalist

The microscopic architect of your backyard pond, Difflugia acuminata builds its own armor out of sand. This incredible 'testate' amoeba carries its house on its back, roaming the underwater forests of silt and moss.

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Quick Identification

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Size

150-350 micrometers (0.006-0.014 inches) in length

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Colors

Translucent internal body with a shell ranging from sandy beige to dark brown depending on collected minerals

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Key Features

Cylindrical or acorn-shaped shell (test) made of sand grains
Distinctly pointed apex at the top of the shell
Clear, finger-like pseudopodia used for movement
Single large opening (aperture) at the base

When You’ll See Them

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Activity pattern Active day and night

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Peak hours Continuous activity

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Season Year-round (most active Spring-Autumn)

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Diet Primarily grazes on bacteria, microscopic algae (diatoms), and organic debris found in aquatic sediments.

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Habitat Freshwater pond sediments, peat bogs, lake bottoms, and damp mosses.

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Where Does the Difflugia Live?

The Difflugia acuminata is a cosmopolitan inhabitant of freshwater ecosystems found across nearly every continent. While they are most documented in the temperate regions of North America, Europe, and Asia, they are virtually ubiquitous in any healthy, moisture-rich environment ranging from backyard ponds to remote alpine lakes. Because they can enter a dormant state, they are easily dispersed by wind or water, allowing them to colonize almost any suitable body of water worldwide.

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9 Countries

100M km² Range

Least Concern Conservation

US United States CA Canada GB United Kingdom DE Germany Russia CN China JP Japan AU Australia BR Brazil

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iNaturalist / Verified observation data

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Behavior

Difflugia (Cylindrifflugia acuminata) is a master architect of the microscopic world. Unlike many other amoebae that are completely soft-bodied, this species constructs a protective 'mobile home' known as a test. It selectively gathers sand grains, mineral particles, or even the discarded shells of diatoms from its environment, gluing them together with a specialized organic cement produced within its cell. This armor provides protection from smaller predators while the amoeba dwells in the silt of pond bottoms.

Movement is slow and deliberate. The amoeba extends lobe-like 'false feet' called pseudopodia through the opening at the bottom of its shell to anchor itself and pull its heavy house forward. It is a solitary creature, spending its entire life cycle within its shell, only emerging partially to feed or to build a new shell during the process of cell division.

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Camera Tips

To capture Difflugia acuminata, you cannot use a standard trail camera; you will need a specialized AI-powered microscopy camera or a digital microscope attachment for your phone. Start by collecting a 'sludge' sample from the bottom of a backyard pond or squeezing the water out of a handful of damp moss. Place a few drops of this liquid onto a well-slide, which allows the amoeba space to move without being crushed by the cover slip.

For the best visual results, use 'Darkfield' or 'Phase Contrast' illumination if your camera supports it. This creates a high-contrast image where the amoeba's translucent body glows against a dark background, highlighting the rough, pebbled texture of its sand-grain shell. Because these creatures are benthic, focus your lens on the very bottom of the slide where they crawl along the glass surface.

Set your camera to a high-frame-rate video mode or a time-lapse setting with 1-second intervals. While they appear still to the naked eye, a time-lapse will reveal the fascinating way they extend their pseudopodia to drag their heavy shells. If you are using AI detection, calibrate it to recognize the distinct 'acorn' shape of the test, as the sand grains can sometimes confuse software looking for organic curves.

Similar Species

Species that look similar or are commonly confused with Difflugia.

Difflugia oblonga

Oblonga is more pear-shaped and lacks the distinct, sharp pointed tip at the end of the shell.

Arcella vulgaris

Arcella builds a smooth, brownish, dome-shaped shell made of chitin rather than sand grains.

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Frequently Asked Questions

Difflugia acuminata are active 24 hours a day. Their activity is governed by moisture and temperature rather than light cycles, though they are easiest to observe when the water is warm.

You can 'attract' them by creating a healthy micro-ecosystem. A small pond with a layer of natural sediment or a 'moss wall' kept consistently damp will provide the perfect habitat for these organisms to thrive.

They are omnivorous micro-scavengers that eat bacteria, small algae like diatoms, and tiny fragments of decaying plant matter found in pond sludge.

Yes, they are extremely common. They can be found in almost any suburban birdbath, garden pond, or damp patch of garden soil throughout the world.

The key is the shell: look for a cylindrical shape made of glued sand grains with a characteristic sharp point at the top. Most other common amoebae either have no shell or have smooth, translucent shells.

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