Muddy Arrowtooth Eel

Ilyophis brunneus

Fish
IUCN: Least concern

Usual depth800–2,775 m
Water temperature-2–29 °C
Best monthsJuly and August
How commonRare

About this species

The muddy arrowtooth eel, Ilyophis brunneus, is a cutthroat eel in the family Synaphobranchidae. It is found around the world at depths below 1,000 m. Its length is up to 160 cm.

Text from the Wikipedia article “Muddy arrowtooth eel”, licensed CC BY-SA 4.0. Read the article

Where and when

Where it has been recorded

Worldwide

Loading the map

Best months

Worldwide (open data)

January: 10 records
February: 6 records
March: 6 records
April: 4 records
May: 7 records
June: 5 records
July: 18 records
August: 28 records
September: 6 records
October: 4 records
November: 6 records
December: 6 records

Depth and water temperature

Depth

Mostly recorded at 800–2,775 m · Deepest record: 4,845 m

420–430 m: 1 records
430–440 m: 0 records
440–450 m: 0 records
450–460 m: 0 records
460–470 m: 0 records
470–480 m: 0 records
480–490 m: 0 records
490–500 m: 0 records
500–510 m: 0 records
510–520 m: 0 records
520–530 m: 0 records
530+ m: 95 records

Water temperature

Recorded in surface water of -2–29 °C

-2–0 °C: 1 records
0–2 °C: 0 records
2–4 °C: 0 records
4–6 °C: 0 records
6–8 °C: 0 records
8–10 °C: 0 records
10–12 °C: 10 records
12–14 °C: 18 records
14–16 °C: 3 records
16–18 °C: 35 records
18–20 °C: 10 records
20–22 °C: 11 records
22–24 °C: 6 records
24–26 °C: 5 records
26–28 °C: 10 records
28–30 °C: 8 records

Names and classification

English: Muddy Arrowtooth Eel, Muddy Cutthroat Eel, ooze eel

Names in 2 more languages

Japanese: Ryukyuhoraanago, リュウキュウホラアナゴ
Simplified Chinese: 合鰓鰻, 褐泥蛇鰻, 軟泥鰻

Similar species

Ilyophis nigeli
Kaup's arrowtooth eel
Synaphobranchus kaupii
Basketwork eel
Diastobranchus capensis
Parasitic eel
Simenchelys parasitica
Grey cutthroat eel
Synaphobranchus affinis
Atractodenchelys robinsorum

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).
217 open-data records from 1883 to 2021.
Species data updated November 3, 2026.

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