--- title: "White-Spotted Pufferfish (Torquigener albomaculosus) | AnimalTracks.wiki" description: "A 12-centimeter pufferfish that spends 7 to 9 days digging a sand circle about 2 meters wide to impress a date." image: "https://animaltracks.wiki/images/animals/japanese-pufferfish-1.webp" published: "2026-08-30" updated: "2026-10-05" --- # White-Spotted Pufferfish (*Torquigener albomaculosus*) > **Status**: Checked against 3 sources, listed under Sources below. > **Tagline**: A 12-centimeter pufferfish that spends 7 to 9 days digging a sand circle about 2 meters wide to impress a date. > **Soundtrack Vibe**: Krautrock & Electronic Pioneers // Kraftwerk, "The Robots" > **Soundtrack Links**: [Spotify](https://open.spotify.com/track/5eqZWYQ5tbIehx00NeKXz7) > **Vibe Match**: A male of about 120 mm swims straight lines for 7 to 9 days, about 10,000 digs, and a 2 m ridged circle appears; a simulation suggests simple repeated moves can rebuild the pattern. Kraftwerk's sequencer loops: one motion repeated until the machine draws the shape. ## Biological Superpowers & Stats - **Taxonomy**: *Torquigener albomaculosus* - **Danger Level**: Low - **Conservation Status**: Not Evaluated ([IUCN Red List](https://www.iucnredlist.org/)) - **Superpower**: Sand architecture: digs a circle about 2 meters wide, ridged like a wheel, with its fins - **Habitat**: Sandy seabed off Amami-Oshima, in the Ryukyu Islands of southern Japan, seen by divers at 10 to 27 meters and around 30 meters - **Diet**: Not stated by the sources on this page - **Tags**: fish, ocean, architect-builder ## Natural History & Behavior ## A Crop Circle Under the Sea In 1995, divers off Amami-Oshima, an island in southern Japan, found a geometric circle about 2 meters across on the sandy seabed. Nobody knew what made it, and the divers named it a "mystery circle." In 2011, scientists first caught the builder at work. It was a male **white-spotted pufferfish** (*Torquigener albomaculosus*), about 120 millimeters long. FishBase gives a maximum of 12.0 cm total length for a male and 9.1 cm standard length (snout to tail base) for a female. ## About 10,000 Digs The male starts by pushing his belly into the sand to mark the center. Then he swims in straight lines from the outside toward the middle, digging with his pectoral, anal and tail fins. One study estimated about 10,000 digs for a whole nest. The job takes 7 to 9 days, and the finished circle has a radius of 79 to 105 centimeters. Each valley is as wide as the male's body, and a flat central zone of 31 to 50 centimeters in radius is left in the middle. A computer simulation built from a male's recorded digs reproduced the radial ditches of the outer ring, suggesting that simple repeated moves can make the pattern. ## Decorated for a Date Near the end, the male places shell and coral fragments on the ridges. He also flaps his anal fin over the center to draw an irregular pattern in fine sand, which the ridges help funnel inward. Females were seen visiting only at this final stage. As one approaches he stirs up the sand, and when she enters he rushes at her several times. She stays about a minute, and often comes back. The eggs are released in the center. In 2013 the researchers wrote that three features of this nest had never been reported in any fish: ridges built around the nest site, shell decorations on them, and a pattern of fine sand in the middle. > **Built to be wrecked** After spawning, the male stays 6 days to care for the eggs and does no repairs. Currents smooth the circle almost flat. No male in the study went back to an old nest: each built a new one at a separate site. ## A Very Small Neighborhood When the first study came out in 2013, this fish had been found only off southern Amami-Oshima, in small numbers and in very restricted areas. FishBase now adds another population at around 30 meters off the island's north. Divers have seen it at 10 to 27 meters on sandy bottom. In a flow experiment on a half-scale model of a circle, the current in the center was 24.2% lower than outside. ## Frequently Asked Questions ### How big is the white-spotted pufferfish, and how big is its circle? The builder is a male about 120 millimeters long. His circle is roughly 2 meters across, with 24 to 32 pairs of ridges and valleys fanning out from the middle. *(Source: [Kawase, Okata & Ito 2013]())* ### Why does the male build a circle? Females were seen visiting a nest only in the final stage of building, once the circle was complete. The researchers think the female judges his work, though they could not say which feature she scores: the size, the ridges, the shells or the fine sand in the middle. *(Source: [Kawase, Okata & Ito 2013]())* ### Does the pufferfish use the same circle twice? No. By the time the eggs hatch, coarser sand has covered the fine sand in the middle and the ridges have washed almost flat. He starts again somewhere else. The authors suggest the valleys do not hold enough fine sand for a second round of eggs. *(Source: [Kawase, Okata & Ito 2013]())* ### How does such a small fish draw such a regular pattern? Researchers filmed one male building a nest in 2016 and logged where each ditch started, how long it ran and which way it pointed. A simulation that followed those rules drew the circle pattern, which suggests repeating simple actions can make it. *(Source: [Mizuuchi et al. 2018]())* ## Sources 1. [Kawase, Okata & Ito (2013). Role of Huge Geometric Circular Structures in the Reproduction of a Marine Pufferfish. Scientific Reports.]() 2. [Mizuuchi et al. (2018). Simple rules for construction of a geometric nest structure by pufferfish. Scientific Reports.]() 3. [Torquigener albomaculosus, White-spotted pufferfish. FishBase.]() *Published August 30, 2026. 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