Fish Active day and night

Western Tubenose Goby

Proterorhinus semilunaris

iNaturalist Wikipedia

With snorkel-like nostrils and a suction-cup belly, the Western Tubenose Goby is a fascinating master of the riverbed. Once confined to the Black Sea, this resilient little fish is now making a splash in waters across the globe.

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Quick Identification

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Size

6–12 cm (2.4–4.7 inches) in length; maximum weight is approximately 10–15 grams (0.35–0.53 oz)

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Colors

Mottled patterns of light brown, olive, and tan with dark vertical bars along the flanks and a small dark spot at the base of the tail.

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Key Features

Pair of tubular nostrils extending over the upper lip
Fused pelvic fins forming a suction-like disc
Broad, flattened head with high-set eyes
Two distinct dorsal fins, the first with yellowish margins

When You’ll See Them

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Activity pattern Active day and night

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Peak hours 6-10 AM, 5-9 PM

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Season April-September

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Diet A benthic carnivore that feeds on aquatic insect larvae (particularly midges), small crustaceans, amphipods, and occasionally fish eggs or very small fry.

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Habitat Slow-moving freshwater or brackish environments with plenty of cover, such as rocky lake bottoms, weed beds, and submerged timber.

Behavior

The Western Tubenose Goby is a cryptic bottom-dweller known for its sedentary lifestyle and remarkable ability to blend into its surroundings. Unlike many fish that swim in the water column, this species spends most of its time perched on its pelvic fins, which are fused into a suction cup, allowing it to anchor itself against currents on rocks or submerged logs. It is a highly territorial species, especially during the breeding season when males guard nesting cavities in rocks or empty mollusk shells.

As a 'sit-and-wait' predator, it remains motionless for long periods before darting out to ambush small prey. While they are generally solitary, they can reach high population densities in invasive ranges. They are relatively tolerant of poor water quality and varying salinities, which has contributed to their success as an invasive species in North America and Europe. They rarely interact with humans directly but are frequently encountered by anglers and citizen scientists using underwater cameras.

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Camera Tips

Capturing the Western Tubenose Goby requires an underwater setup, such as an action camera in a waterproof housing or a dedicated submersible trail camera. To get the best shots, place your camera in shallow water (1–3 feet deep) near rocky structures or submerged logs, as these fish rarely venture far from cover. Angle the lens slightly downward toward a flat rock or a small sandy clearing between stones where the goby is likely to 'perch' on its suction-cup fins.

Because these fish are small and well-camouflaged, clarity is key. Place your camera in an area with minimal silt to prevent 'backscatter' in your footage. You can encourage a visit by placing a 'bait station' just inside the camera's focal range—a small mesh bag containing crushed snails or frozen bloodworms is highly effective. Be sure to set your camera to a close-focus mode or use a macro lens if available, as the goby's most defining feature, the tubular nostrils, requires a close-up to see clearly.

Lighting is the biggest challenge underwater. If your backyard setup is in a shaded area, consider using a small, diffused waterproof LED light to bring out the mottled brown and gold colors of the fish. Early morning and late afternoon provide the best natural light penetration in shallow water. In invasive regions, look for them in marinas or near piers, as they love the artificial cover provided by human structures.

Similar Species

Species that look similar or are commonly confused with Western Tubenose Goby.

Round Goby

Lacks the tubular nostrils and features a prominent large black spot on the first dorsal fin.

Mottled Sculpin

Has separate pelvic fins rather than a fused suction disc, and lacks the snorkel-like nostrils.

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Frequently Asked Questions

Western Tubenose Gobies are active throughout the day and night, but they show significant peaks in activity during the crepuscular hours of dawn and dusk when they emerge from under rocks to hunt for insect larvae.

If you live near a freshwater lake or river where they are present, place an underwater camera near rocky crevices. Use a small amount of fish-based bait or crushed aquatic snails in a mesh bag to lure them into the frame.

They are bottom-feeders that primarily eat benthic invertebrates, including midges, caddisfly larvae, and small crustaceans like scuds. In some areas, they may also consume the eggs of larger fish species.

Yes, in their invasive range (like the Great Lakes region), they are very common in suburban canals, marinas, and park ponds with rocky shorelines.

The easiest way is to look at the nostrils: the Tubenose Goby has two distinct tube-like protrusions extending over its lip, whereas the Round Goby does not. Additionally, the Round Goby usually has a very prominent black spot on its first dorsal fin.

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