🪐 View in 3D Galaxy 📏 View on 3D Scale Stage

🧬 Biological Classification (Kingdom to Species)Odontobutis obscurus

Kingdom

Animalia

Phylum

Chordata

Class

Actinopteri

Order

Gobiiformes

Family

Odontobutidae

Genus

Odontobutis

Species

Odontobutis obscurus

📏 True-scale comparison (1 m = 1 m) against a 1.75 m humanLength 17.5cm

🔍 Zoomed View — Same scale as a credit card & 2.65cm coin

· Grid units represent actual meters (m); human and animals are drawn to the exact same scale with original silhouette aspect ratios preserved.
· When a size range is recorded (e.g. 1–1.6m), the lower bound is used for scale comparison.
· Dark sleeper silhouette: PhyloPic — author not recorded · CC0 1.0 (Odontobutis obscura)
· Human silhouette: PhyloPic — NASA · Public Domain Mark 1.0

• Length vs. 1.75 m human: 0.1× Compare with other species →

Actinopteri🥩 Carnivore

Dark sleeper

Odontobutis obscurus (Dark sleeper · Dark sleeper)

🛡️ Conservation Status (IUCN Red List)LC (Least Concern)

DDData Deficient

LCLeast Concern

NTNear Threatened

VUVulnerable

ENEndangered

CRCritically End.

EWExtinct in Wild

EXExtinct

🇰🇷 Class I endangered wildlife (Korea)

Geological Era

Extant

Diet

Carnivore

Length · Height

17.5cm · No data

Mass · Top Speed

No data · No data

Habitat & Fossil Locality

Slow-moving margins of middle and lower river reaches with aquatic vegetation and gravel or mud bottoms; southwestern Japan and southern China

💡 Everyday Comparisons for Size, Mass & Speed

💡 Its maximum length of 17.5 cm is about twice the long side of a credit card (8.56 cm) (Comparison).
💡 According to the National Institute of Ecology, the presence of this fish is considered evidence that Korean and Japanese rivers were connected during the Ice Age, and today it can be found at only one site, Sanyangcheon Stream on Geojedo Island.

Reference standards: coach bus ~12 m, mid-size car ~4.9 m, compact car ~1 t, basketball hoop 3.05 m, credit card 8.56 cm.

#남방동사리#Odontobutis obscurus

📖 1. Overview

The dark sleeper is a freshwater fish of the family Odontobutidae and a Class I endangered wildlife (Korea) species that in Korea lives only in Sanyangcheon Stream on Geojedo Island, Gyeongsangnam-do. It is mainly active at night.

🦴 2. Anatomy & Morphology

The front of its body is cylindrical and the rear is laterally compressed. Its body is dark brown with a yellow belly, cloud-like dark brown blotches along the flanks, and a dorsal fin divided into two.

🔍 3. Ecology & Behavior

It feeds on aquatic insect larvae, crustaceans, and fish. From April to July, the male prepares a spawning site under a large stone and guards the eggs until they hatch.

🇰🇷 4. Connection to Korea

Both the National List of Species of Korea and the National Institute of Ecology list it as a Class I endangered wildlife (Korea) species. First reported in Korea in 1999 and known only from Sanyangcheon Stream on Geojedo Island, its numbers are declining due to water pollution and river development.