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The Fifteen-spined stickleback (Spinachia spinachia) is a distinctive marine fish belonging to the family Gasterosteidae. It is characterized by its elongated body, numerous dorsal spines, and a preference for coastal, vegetated habitats. Unlike its freshwater relatives, it is exclusively found in saline environments.
Physical Characteristics
- Body shape
- elongated
- Coloration
- Typically mottled brown to olive-green on the dorsal side, fading to a lighter, often silvery or yellowish belly. This coloration provides excellent camouflage among marine vegetation. During breeding, males may exhibit more vibrant hues.
- Scale type
- none
- Mouth position
- superior
- Distinctive features
- 14-16 (typically 15) free, sharp dorsal spines, followed by a soft-rayed dorsal fin., Elongated, slender body, much more so than other stickleback species., Small, upturned mouth., Absence of scales, instead covered by bony plates along the lateral line.
- Dorsal fin
- Composed of 14-16 isolated, sharp spines followed by a single soft-rayed fin (1 spine, 6-7 soft rays).
- Tail fin
- Rounded to slightly emarginate caudal fin.
- Pectoral fin
- Relatively small and rounded, positioned laterally.
- Distinctive fins
- Two small, sharp pelvic spines and one soft ray. Anal fin with 1 spine and 6-7 soft rays.
Identification Tips
Dorsal Spines
Count the number of free, sharp spines along the back. The Fifteen-spined stickleback consistently has 14-16, distinguishing it from other stickleback species which have fewer (e.g., Three-spined, Nine-spined).
Body Shape
Its body is notably more elongated and slender compared to the more robust and deeper-bodied freshwater sticklebacks.
Habitat
Always found in marine or brackish environments, never in pure freshwater, which helps differentiate it from other stickleback species that are primarily freshwater or anadromous.
Mouth Position
The small, upturned mouth is characteristic and adapted for picking small invertebrates from vegetation.
Habitat
- Water type
- saltwater
- Depth
- Typically found in shallow coastal waters, from the intertidal zone down to about 10-20 meters.
- Environment
- Prefers areas with dense marine vegetation, such as seagrass beds (e.g., Zostera marina), kelp forests, and rocky shores with abundant macroalgae. They use this vegetation for camouflage, shelter, and nesting sites.
- Geographic range
- Northeastern Atlantic Ocean, ranging from the White Sea and Norway south to the Bay of Biscay, including the British Isles, the North Sea, and the Baltic Sea.
Aquarium Information
- Care level: advanced
- Temperament: semi-aggressive
- Diet: carnivore
- Minimum tank size: 75 gallons (280 liters)
- Temperature: 10-18°C (50-64°F)
- pH level: 7.8-8.4
- Hardness: High (marine salinity)
- Compatibility: Best kept in a species-specific tank or with other robust, non-aggressive marine species of similar size that can tolerate cooler water. Avoid small, delicate fish or those that might be prey.
- Special requirements: Requires a well-established marine aquarium with excellent filtration and stable water parameters. Abundant live rock and marine vegetation (e.g., seagrass, macroalgae) are crucial for providing shelter and mimicking its natural habitat. A strong current is beneficial. They are sensitive to poor water quality and high temperatures.
Wild Information
- Conservation status: least concern
- Seasonality: Breeding occurs primarily from April to July, with males building elaborate nests in marine vegetation. They are present year-round in their habitat.
- Market price: N/A
- Commercial importance: none
- Taste: Not typically consumed by humans.
- Texture: N/A
- Nutritional value: N/A
Key Facts
Unique Spinesamazing
The Fifteen-spined stickleback possesses the highest number of free dorsal spines among all stickleback species, typically 14-16, which is a key identification feature.
Marine Specialistbehavior
Unlike many other sticklebacks that inhabit freshwater or brackish environments, Spinachia spinachia is exclusively a marine species, rarely venturing into waters of significantly reduced salinity.
Elaborate Nest Builderbehavior
Males construct intricate, barrel-shaped nests from algae and other marine debris, bound together with a sticky secretion from their kidneys. They then guard the eggs and fry diligently.
Camouflage Masteramazing
Its elongated, mottled body provides excellent camouflage among the blades of seagrass and other marine vegetation where it lives, helping it ambush prey and avoid predators.
Short Lifespaninteresting
Fifteen-spined sticklebacks typically have a short lifespan, often only living for one to two years, with most individuals dying after their first breeding season.
Safety Information
Handle with care- Safety level: caution
- Venomous: No
- Edibility: not recommended
- Handling notes: While not venomous, the numerous sharp dorsal and pelvic spines can inflict painful punctures if handled carelessly. Use caution and avoid direct contact with the spines. If handling is necessary, use a net or thick gloves. The fish is delicate and should be returned to water quickly if caught.
Similar Species
Three-spined stickleback
Gasterosteus aculeatus
Has 2-4 (typically 3) dorsal spines, a deeper body, and is primarily found in freshwater or anadromous populations. The Fifteen-spined stickleback has 14-16 spines and is exclusively marine.
Nine-spined stickleback
Pungitius pungitius
Has 7-12 (typically 9) dorsal spines, a more slender body than the Three-spined but less elongated than the Fifteen-spined, and is found in freshwater and brackish environments. The Fifteen-spined stickleback has more spines and is strictly marine.
Scientific Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Actinopterygii
- Order
- Gasterosteiformes
- Family
- Gasterosteidae
- Genus
- Spinachia
- Species
- spinachia
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