(family Cetomimidae)

A network of pores helps this fish feel what goes bump in the dark.

A whalefish lives in the inky depths below 1,000 meters (3,300 feet) called the midnight zone. Its eyes are poorly developed and small—in fact, they lack lenses and are not even capable of forming images. Instead, a whalefish relies on a network of sensory pores that run over the head and down the length of the body. Those pores feel vibrations in the water and allow a whalefish to detect when predators or prey are near. Many fishes have these sensory pores, usually arranged into the lateral line running along their sides. In the whalefish, the pores are quite large and lie along ridges that give the fish a crocodile-like appearance. 

Like many deep-sea animals, whalefishes have a brilliant reddish coloration. Red light does not travel far in seawater and cannot penetrate into the deep sea, so anything red appears black. The intense red color helps a whalefish disappear into the darkness to ambush unsuspecting prey or avoid a hungry predator.

There are 30 species of whalefish in the family Cetomimidae. Most are only 20 centimeters (almost eight inches) long, with the largest species reaching up to 40 centimeters (16 inches) in length. Their name derives from their resemblance to a baleen whale with a broad trunk and a large, gaping mouth for gulping prey. One whalefish MBARI researchers observed had a swollen stomach indicating that it had the recent fortune to gulp in a large fish as prey. 

Whalefishes have rarely been collected alive, so much of their biology remains a mystery. Most research on these fishes has been based on specimens collected by deep-water trawl nets. MBARI’s remotely operated vehicles (ROVs) very rarely encounter these obscure fishes. In the more than 27,000 hours of video MBARI’s ROVs have recorded, we have logged just 16 observations. But each observation offers a valuable chance to learn more about this mysterious resident of the ocean’s midnight zone.

Fast Facts

Maximum Size: 40 centimeters (16 inches)

Depth: 1,500–3,500 meters (4,900–11,500 feet)

Habitat: midwater, in the twilight (mesopelagic) and midnight (bathypelagic) zones

Range: worldwide in tropical and temperate waters

Diet: crustaceans, other fishes


Video clips

Research publications

Choy, C.A., S.H.D. Haddock, and B.H. Robison. (2017). Deep pelagic food web structure as revealed by in situ feeding observations. Proceedings of the Royal Society B, 284: 20172116. doi.org/10.1098/rspb.2017.2116

Robison, B.H. (2004). Deep pelagic biology. Journal of Experimental Marine Biology and Ecology, 300: 253-272. doi.org/10.1016/j.jembe.2004.01.012

Robison, B.H., R.E. Sherlock, and K.R. Reisenbichler (2010). The bathypelagic community of Monterey Canyon. Deep-Sea Research Part II, 57(16): 1551-1556. doi.org/10.1016/j.dsr2.2010.02.021


Data repository
Data policy
Deep-Sea Guide
What is happening in Monterey Bay today?
Central and Northern California Ocean Observing System
Chemical data
Ocean float data
Slough data
Mooring ISUS measurements
Southern Ocean Data
Mooring data
M1 Mooring Summary Data
M1 Asimet
M1 download Info
M1 EMeter
Molecular and genomics data
ESP Web Portal
Seafloor mapping
Soundscape Listening Room
Upper ocean data
Spatial Temporal Oceanographic Query System (STOQS) Data
Image gallery
Video library
Creature feature
Deep-sea wallpapers
Previous seminars
David Packard Distinguished Lecturers
Research software
Video Annotation and Reference System
System overview
Data Use Policy
Video Tape User Guide
Video File User Guide
Annotation Glossary
Query Interface
Basic User Guide
Advanced User Guide
Query Glossary
VARS publications
VARS datasets used in publications
Oceanographic Decision Support System
MB-System seafloor mapping software
How to download and install MB-System
MB-System Documentation
MB-System Announcements
MB-System Announcements (Archive)
MB-System FAQ
MB-System Discussion Lists
MB-System YouTube Tutorials
Matlab scripts: Linear regressions
Introduction to Model I and Model II linear regressions
A brief history of Model II regression analysis
Index of downloadable files
Summary of modifications
Regression rules of thumb
Results for Model I and Model II regressions
Graphs of the Model I and Model II regressions
Which regression: Model I or Model II?
Matlab scripts: Oceanographic calculations
Matlab scripts: Sound velocity
Visual Basic for Excel: Oceanographic calculations
Educational resources
Navigating STEM careers
MBARI Summer Internship Program
2017 Summer Interns Blog
Education and Research: Testing Hypotheses (EARTH)
EARTH workshops
2016—New Brunswick, NJ
2015—Newport, Oregon
2016 Satellite workshop—Pensacola, FL
2016 Satellite workshop—Beaufort, NC
EARTH resources
EARTH lesson plans
Lesson plans—published
Lesson plans—development
Lesson drafts—2015
Lesson drafts—2016 Pensacola
Adopt-A-Float Program
Center for Microbial Oceanography: Research and Education (C-MORE) Science Kits
Science at home: Curriculum and resources
Sample archive
SciComm Resources