How do sticklebacks differ from cornetfishes?

While both sticklebacks and cornetfishes belong to the order Gasterosteiformes, they differ significantly in size, physical structure, and anatomy.123

• Size: Sticklebacks are small, reaching a maximum length of about 18 cm (7 inches). In contrast, cornetfishes are extremely long and slim, growing to lengths of more than 200 cm (6.6 feet).143
• Body Shape and Armor: Sticklebacks have a fusiform (tapered) body shape and are generally scaleless, though they may have bony plates on their sides. Cornetfishes are flattened from top to bottom, lack scales, and have bony plates embedded in their skin.143
• Spines and Fins: Sticklebacks are characterized by 2 to 16 free spines on their back in front of the dorsal fin. Cornetfishes lack dorsal spines entirely. Additionally, the cornetfish possesses a unique long filament extending from the end of its backbone beyond its forked tail fin, a feature absent in sticklebacks.143
• Snout: Sticklebacks have short jaws, whereas cornetfishes possess an elongated tubular snout.43