- · 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.
- · Rapids gudgeon silhouette: PhyloPic — Douglas Teles da Rosa · CC0 1.0 (Tanichthys albonubes)
- · Human silhouette: PhyloPic — NASA · Public Domain Mark 1.0
Rapids gudgeon
Microphysogobio rapidus (Rapids gudgeon · Rapids gudgeon)
🇰🇷 Class I endangered wildlife (Korea)
💡 Everyday Comparisons for Size, Mass & Speed
- 💡 Its maximum body length of 10 cm is shorter than a ballpoint pen (about 14 cm) and slightly longer than the long side of a credit card (about 8.56 cm) (Comparison).
- 💡 Because it is among the first fish to decline when riffles disappear due to river construction and water pollution, it is closely tied to local river construction news.
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.
📖 1. Overview
The rapids gudgeon is a small freshwater fish living in fast riffles of the Nakdong River system, now confirmed only around the Namgang River.
🦴 2. Anatomy & Morphology
Its trunk is horizontally elongated and slightly flattened from top to bottom, with a horseshoe-shaped mouth set beneath the snout. During the spawning season, the gill cover turns blue, the area above the lateral line turns green, and the pectoral fins turn red.
🔍 3. Ecology & Behavior
It feeds mainly on attached algae but also eats small crustaceans and aquatic insect larvae. During the April–May spawning season, it is often seen in gravelly riffles.
🇰🇷 4. Connection to Korea
It is a Class I endangered wildlife (Korea) species endemic to Korea. It once lived at more than 10 sites in the Nakdong River system, but is now confirmed only around the Namgang River.
📚 Sources & References
- • IUCN Red List CR (2023) — https://www.iucnredlist.org/species/148448254/148448300
- • 멸종위기 야생생물 Ⅰ급 — 국가생물종목록(국립생물자원관) ktsn 120000057589 — https://species.nibr.go.kr/home/mainHome.do?cont_link=009&subMenu=009002&contCd=009002&ktsn=120000057589
- • IUCN Red List category CR — latest assessment at iucnredlist.org
- • Korean protection status: Class I endangered wildlife (Korea)
- • catalogueoflife.org — 433HQ
- • iucnredlist.org — 148448300
- • 국가생물종목록(국립생물자원관) ktsn 120000057589 — https://species.nibr.go.kr/home/mainHome.do?cont_link=009&subMenu=009002&contCd=009002&ktsn=120000057589
- • wikidata.org — Q5751553
- • species.nibr.go.kr — list
- • Silhouette: PhyloPic — Douglas Teles da Rosa · CC0 1.0 (Related taxon silhouette — Tanichthys albonubes)
Recorded dimensions are widely cited representative estimates from public literature and may vary by study or specimen.