Ratfish

Hydrolagus colliei

Fish
IUCN: Least concern

Usual depth43–207 m
Water temperature5–14 °C
Best monthsJune
How commonCommon

Photo credit: (c) Brian Gratwicke, some rights reserved (CC BY) · CC BY · iNaturalist

About this species

The spotted ratfish is a chimaera found in the north-eastern Pacific Ocean. Often seen by divers at night in the Pacific Northwest, this cartilaginous fish gets its characteristic name from a pointed rat-like tail. The ratfish lays leathery egg cases on the bottom of muddy or sandy areas, which are often mistaken by divers as something inanimate. While mainly a deep-water species, it occurs at shallower depths in the northern part of its range. The generic name, Hydrolagus, comes from the Greek words ὕδωρ, meaning water, and λαγώς/λαγῶς, meaning hare, and the specific name honors Alexander Collie, who was a ship's surgeon and early naturalist who dissected the first specimen to be described during the voyage of HMS Blossom in the Pacific from 1825-28. The spotted ratfish is common in much of its range, not typically eaten by humans, and is not commercially caught.

Text from the Wikipedia article “Spotted ratfish”, licensed CC BY-SA 4.0. Read the article

Where and when

Where it has been recorded

Worldwide

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Best months

Worldwide (open data)

January: 91 records
February: 77 records
March: 106 records
April: 245 records
May: 7,092 records
June: 13,831 records
July: 3,820 records
August: 1,174 records
September: 724 records
October: 201 records
November: 82 records
December: 60 records

Depth and water temperature

Depth

Mostly recorded at 43–207 m · Deepest record: 487 m

0–10 m: 7 records
10–20 m: 54 records
20–30 m: 495 records
30–40 m: 697 records
40–50 m: 1,156 records
50–60 m: 1,417 records
60–70 m: 1,276 records
70–80 m: 956 records
80–90 m: 1,031 records
90–100 m: 900 records
100–110 m: 1,064 records
110+ m: 7,673 records

Water temperature

Recorded in surface water of 5–14 °C

4–6 °C: 1 records
6–8 °C: 0 records
8–10 °C: 670 records
10–12 °C: 321 records
12–14 °C: 1 records
14–16 °C: 1 records

Photos

(c) Stosh Morency, some rights reserved (CC BY), uploaded by Stosh Morency · CC BY · iNaturalist
(c) Clark Anderson/Aquaimages, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
(c) Stosh Morency, some rights reserved (CC BY), uploaded by Stosh Morency · CC BY · iNaturalist
(c) J Straka, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Aiva Noringseth, some rights reserved (CC BY) · CC BY · iNaturalist
(c) Irina Mitine, some rights reserved (CC BY) · CC BY · iNaturalist
no rights reserved · CC0 1.0 · iNaturalist

Names and classification

English: Ratfish, Spotted ratfish, ratfish, spotted ratfish, White-spotted Ratfish

Names in 3 more languages

German: Gefleckte Pazifische Chimäre, Gefleckte Seeratte
Spanish: quimera manchada
French: chimère d'Amérique, chimère d’Amérique

Other scientific names: Chimaera colliei, Chimaera media, Chimaera neglecta, Hydrolagus media

Similar species

Dark Chimaera
Hydrolagus novaezealandiae
Pale Brown Chimaera
Hydrolagus bemisi
African chimaera
Hydrolagus africanus
Black Chimaera
Hydrolagus homonycteris
Philippine Chimaera
Hydrolagus deani
Marbled Ghostshark
Hydrolagus marmoratus

Sources and credits

Names and taxonomy: WoRMS (CC BY 4.0) and the GBIF Backbone (CC BY 4.0). Photos: iNaturalist observers, each under the licence shown (CC0, CC BY or CC BY-SA).

Depth, temperature, months and maps: records from OBIS and GBIF under CC0 or CC BY.
Descriptions: Wikipedia, licensed CC BY-SA, each linked to its article.
Conservation status as published by GBIF (IUCN Red List).
109,303 open-data records from 1888 to 2024.
Species data updated November 3, 2026.

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