What Midshipman Fish Are
Midshipman fish are small, bottom-dwelling saltwater fish found along the Pacific coast of North America. They belong to the family Batrachoididae, which also includes toadfish. The name comes from the rows of light-producing organs (called photophores) that run along their sides, resembling the buttons on a naval officer's uniform. These fish typically grow 6 to 10 inches long, though some reach 12 inches.
The most distinctive feature of midshipman is their ability to produce sound. During spawning season, males make loud grunting and humming noises by vibrating their swim bladders — a behavior so pronounced that coastal residents in California and Oregon have reported hearing the sounds through boat hulls and even from the shore. The fish are not aggressive toward anglers, but they are rarely targeted intentionally because they are small and offer little sport value.
Midshipman are nocturnal hunters that feed on small crustaceans, larval fish, and other invertebrates. They spend daylight hours buried in sand or mud on the seafloor, emerging at night to feed. This behavior makes them difficult to encounter unless you are fishing at night or in deep water where light levels are naturally low.
Key Takeaways
- Midshipman fish are small Pacific coast residents that produce light and make loud underwater sounds during breeding season.
- They live on the seafloor in shallow to moderate depths and are most active at night.
- Midshipman are rarely kept as food fish and are not a target species for recreational anglers.
- If you catch one, it is harmless to handle, though the fish may make audible grunting sounds.
Where Midshipman Live Along the Pacific Coast
Midshipman are found from Baja California north to British Columbia, with the highest concentration along the coasts of California and Oregon. They prefer rocky reefs, sandy bottoms, and muddy substrates in depths ranging from the low intertidal zone down to about 600 feet, though most fishing encounters occur in shallower water under 100 feet.
In California, they are common in bays and estuaries, including San Francisco Bay, Monterey Bay, and the waters around the Channel Islands. Oregon anglers fishing rocky areas off the central and southern coast may encounter them. In Washington state, they are present but less frequently reported by recreational fishermen. The fish tend to concentrate in areas with good shelter — crevices, kelp holdfasts, and soft substrate where they can burrow.
Seasons and Spawning Behavior
Midshipman spawn from late spring through early fall, with peak activity in June and July. During this period, males move into shallow water to establish nesting sites in sand or gravel. This is when the sound production becomes most intense — males call to attract females and defend territory. The loud humming and grunting can reach 130 decibels underwater and has been mistaken for boat engines or mechanical noise by people unfamiliar with the fish.
Outside the spawning season, midshipman are less vocal and remain in deeper water. Winter months (November through February) see them retreat to greater depths. If you are fishing in shallow bays or near shore during summer and hear unusual underwater sounds, you may be listening to a midshipman chorus.
How to Catch Midshipman (If You Want To)
Midshipman are not a target species, but you will occasionally catch them while fishing for other bottom-dwelling fish like rockfish, lingcod, or cabezon. They bite small baits — pieces of squid, anchovy, or shrimp — fished on or near the bottom. Light tackle works well because of their small size. Night fishing in shallow bays increases your chances of an encounter.
If you do hook one, the fish will put up minimal resistance. They are not known for running or fighting hard. Once landed, they are safe to handle, though they may produce audible grunting sounds — a defensive behavior that can startle an angler unfamiliar with the species. Simply wet your hands before handling to protect their skin, and return them to the water if you do not intend to keep them.
Regulations and Keeping Midshipman
Midshipman have no minimum size limit and no bag limit in California, Oregon, or Washington. However, there is little reason to keep them. They are not considered food fish in North America, and their small size means minimal meat yield. Some aquarium hobbyists have kept them in saltwater tanks, where they will burrow into sand and produce their characteristic sounds, but they are not widely available through the aquarium trade.
Check your state's current fishing regulations before you fish, as rules can change. California Department of Fish and Wildlife, Oregon Department of Fish and Wildlife, and Washington Department of Fish and Wildlife all publish online guides that list species-specific rules.
Why Midshipman Matter to Anglers
Midshipman are not a prize catch, but they are an important part of the Pacific coastal ecosystem. They serve as prey for larger fish, seals, and seabirds. Understanding their presence and behavior can help you interpret what you encounter while fishing. If you are fishing rocky reefs or sandy bottoms at night and catching small, odd-looking fish with light organs, you now know what they are.
The fish are also a reminder that the ocean is full of creatures with unusual adaptations. The ability to produce both light and sound makes midshipman one of the more remarkable small fish in North American waters, even if they will never make it into a fishing tournament.
Frequently Asked Questions
Are midshipman fish poisonous or dangerous to handle?
No. Midshipman are harmless to handle. They have no venomous spines or teeth large enough to cause injury. The grunting sound they produce is a defensive behavior, not a threat. Wet your hands before handling to protect their skin, and they can be safely returned to the water.
What is that humming sound I hear underwater near the shore?
During spawning season (June through July), male midshipman produce loud humming and grunting sounds by vibrating their swim bladders. The noise can be heard through boat hulls and sometimes from the shore. It is a mating call and territorial display, not a sign of danger.
Can you eat midshipman fish?
Technically yes, but they are not eaten in North America. They are too small to yield much meat, and they are not marketed as food. Some cultures in other parts of the world use small fish of this type, but midshipman have no culinary tradition here.
Do midshipman fish glow in the dark?
Midshipman have light-producing organs called photophores, but they do not glow brightly enough to be seen in the dark by the human eye. The light is used for communication and possibly camouflage in deep water. You would need specialized equipment to see it.
What do midshipman fish eat?
Midshipman hunt small crustaceans, larval fish, and other invertebrates at night. They are bottom feeders that emerge from their burrows after dark to hunt. Small pieces of squid, anchovy, or shrimp will attract them if you are fishing the seafloor.