Cortez Damselfish
Stegastes rectifraenum
Also calledCortez gregory
Its published range ends at Isla San Martín in northern Baja California. iNaturalist held no California record before November 2026.
Sightings
2026 season, numbered oldest first, every one sourced
- #2Nov 9, 20261 reportMission Beach, San Diego
- Source
- iNaturalist 413882736
- #1Nov 8, 20261 reportLa Jolla CanyonJuvenile
Juvenile Photos: Tory Bush- ID
- Nautical Nick, from Tory Bush's photos
- Source
- Tory Bush photos, sent to Nick, Nov 9
About this fish
What it is, where it comes from, and whether it has been here before
How it lives
Cortez damselfish live on shallow rocky reefs, often in the surge zone. Love and colleagues record them from the intertidal zone, the strip of shore covered and uncovered by the tides, down to about 90 feet. Mexican Fish gives 40 feet as their deepest. They reach about 6.3 inches. They feed by day on algae, small bottom animals and plankton, and they are aggressive when feeding and when defending their territory. Their eggs stick to the bottom, and the males guard and aerate them. The IUCN listed the species as Least Concern in 2007.
Where it normally lives
Isla San Martín in northern Baja California to Peru, including the Gulf of California and the Revillagigedo Islands.
Love and colleagues list the Cortez damselfish from Isla San Martín, off northern Baja California, south to Peru, including the Gulf of California and the Revillagigedo Islands. Mexican Fish describes it as absent from the Pacific coast of Baja north of Guerrero Negro, so the 2 sources disagree about how far north it normally lives. Neither lists California.
Range source: Love and colleagues, 2021 checklist of Pacific coast fishes · FishBase · Mexican Fish.com
In California
On November 8, 2026, Tory Bush photographed a juvenile at La Jolla Canyon, and Nautical Nick identified it as a Cortez damselfish. The next day, a diver at Mission Beach in San Diego posted photos of another one to iNaturalist. The diver first took it for a silverstripe chromis, then noticed the spot on its dorsal fin. iNaturalist held no earlier California record of the species on November 9, 2026.
Photos
More of each life stage
The California photos sit with their numbered sightings above. If you photographed this animal in California this season, send it in.
Identification
How to tell it from the locals
The Cortez damselfish is a small damselfish. Adults are dark brown, lighter brown on the head, with scattered pale spots on the body. Juveniles are colored very differently. Mexican Fish describes them as bright blue with darker scale edges and 2 neon-blue stripes along the top of the head. A black spot ringed in blue sits where the spiny and soft parts of the dorsal fin meet, and a smaller blue-edged black spot sits at the top of the tail base.
Several damselfish look similar. The Acapulco damselfish is lighter on the front half of its body, the beaubrummel has yellow fin tips, the giant damselfish has white-tipped fins, and the whitetail damselfish has a yellow edge on its pectoral fin.
Details
Rarity in the compendium is Nautical Nick's call on how likely a diver is to run into the animal on the California coast this season, not how rare it is where it normally lives.