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Redigobius macrostoma, commonly known as the Spotted Goby, is a small, euryhaline fish belonging to the family Gobiidae. It is characterized by its distinctive spotted coloration and relatively large mouth. This species is often found in brackish and freshwater environments, demonstrating adaptability to varying salinities. It plays a role in its ecosystem as both a predator of small invertebrates and a food source for larger aquatic animals.
Physical Characteristics
- Body shape
- elongated
- Coloration
- The body is typically light brown to yellowish-tan, adorned with numerous dark brown to black spots and blotches irregularly distributed across the flanks and fins. A prominent dark spot is often present at the base of the caudal fin. The ventral side is usually lighter.
- Scale type
- ctenoid
- Mouth position
- superior
- Distinctive features
- Relatively large, upward-pointing mouth (macrostoma means 'large mouth'), Two distinct dorsal fins, Pelvic fins fused into a suction cup-like disc, Irregular dark spots and blotches over the body and fins
- Dorsal fin
- Two dorsal fins; the first dorsal fin has 6-7 spines, and the second dorsal fin has 1 spine and 7-9 soft rays. The first dorsal fin is typically lower than the second.
- Tail fin
- Rounded to slightly emarginate caudal fin.
- Pectoral fin
- Pectoral fins are relatively large and rounded, with 15-18 rays.
- Distinctive fins
- Pelvic fins are completely fused into a prominent, anteriorly directed adhesive disc, characteristic of gobies.
Identification Tips
Mouth Size and Orientation
Look for a noticeably large mouth that is angled upwards, a key feature implied by its scientific name 'macrostoma'.
Body Pattern
Observe the irregular dark spots and blotches scattered across the body and fins. This is the primary characteristic for its common name, 'Spotted Goby'.
Pelvic Fins
Confirm the presence of fused pelvic fins forming a suction cup, a definitive characteristic of gobies.
Dorsal Fins
Note the two separate dorsal fins, with the first being spiny and the second having soft rays.
Habitat
- Water type
- brackish
- Depth
- Typically found in shallow waters, from a few centimeters to a few meters deep.
- Environment
- Inhabits estuaries, coastal lagoons, mangrove swamps, and lower reaches of rivers. Prefers areas with muddy or sandy substrates, often with submerged vegetation or detritus, providing cover. Can tolerate a wide range of salinities, from freshwater to moderately brackish conditions.
- Geographic range
- Indo-West Pacific region, including coastal areas of India, Southeast Asia (e.g., Thailand, Malaysia, Indonesia, Philippines), and extending to parts of Australia and some Pacific islands.
Aquarium Information
- Care level: intermediate
- Temperament: peaceful
- Diet: carnivore
- Minimum tank size: 20 gallons
- Temperature: 22-28°C (72-82°F)
- pH level: 7.0-8.5
- Hardness: 10-25 dGH
- Compatibility: Generally peaceful with similarly sized, non-aggressive fish. Avoid very small or fin-nipping species. Best kept in species-specific tanks or with other brackish water gobies.
- Special requirements: Requires brackish water conditions (specific gravity 1.005-1.015) for optimal health, though can adapt to freshwater. A sandy or fine gravel substrate is preferred, along with plenty of hiding spots created by rocks, driftwood, and dense planting. Good filtration and regular water changes are essential.
Wild Information
- Conservation status: least concern
- Seasonality: Breeding typically occurs during warmer months, but specific seasonal patterns can vary geographically.
- Market price: N/A
- Commercial importance: none
- Taste: N/A
- Texture: N/A
- Nutritional value: N/A
Key Facts
Euryhaline Adaptabilitybehavior
The Spotted Goby is highly adaptable to varying salinities, thriving in both freshwater and brackish environments, which allows it to colonize diverse coastal habitats.
Suction Cup Finsinteresting
Like many gobies, Redigobius macrostoma possesses fused pelvic fins that form a powerful suction cup, enabling it to cling to surfaces in strong currents or during tidal changes.
Ambush Predatorbehavior
With its superior mouth, the Spotted Goby is well-adapted for feeding on small invertebrates from the water column or surface, often ambushing prey from a concealed position.
Territorial Naturebehavior
While generally peaceful, male Spotted Gobies can exhibit territorial behavior, especially during breeding, defending their chosen nesting sites.
Safety Information
Safe- Safety level: safe
- Venomous: No
- Edibility: not recommended
- Handling notes: No specific handling precautions are required beyond standard fish handling practices to minimize stress to the fish. Avoid direct contact with spines to prevent minor punctures.
Similar Species
Knight Goby
Stigmatogobius sadanundio
While also spotted, S. sadanundio typically has more defined, often larger, black spots arranged in rows, and usually exhibits a more robust body shape. Its mouth is not as distinctly large and upward-pointing as R. macrostoma.
Freshwater Goby
Glossogobius giuris
G. giuris is generally larger, has a more elongated and cylindrical body, and its spots are often less distinct or form more of a mottled pattern rather than discrete spots. Its mouth is terminal, not superior.
Scientific Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Actinopterygii
- Order
- Gobiiformes
- Family
- Gobiidae
- Genus
- Redigobius
- Species
- Redigobius macrostoma
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