Ophidiiformes
Ophidiiformes is an order of mostly marine ray-finned fishes that comprises about 200 species. They are known as cusk-eels, brotulas, and pearlfishes, and are found in temperate and tropical waters worldwide. They are distinguished from true eels (Anguilliformes) by having a distinct dorsal fin, a separate anal fin, and a more robust body.
Characteristics
Ophidiiformes possess a range of unique characteristics:
- Elongated, often snake-like body
- Small, often degenerate scales
- Large, often protruding eyes
- Single dorsal fin extending most of the length of the body
- Separate anal fin
- No pelvic fins (except for a few species)
- Barbels, often located near the mouth
- Usually carnivorous, feeding on invertebrates and smaller fish
Environments
Ophidiiformes are found in a variety of marine environments, including:
- Deep sea: Many species inhabit the deep sea, some living at depths exceeding 5,000 meters.
- Coastal waters: Some species are found in shallower waters, often near rocky reefs or sandy bottoms.
- Estuaries: A few species tolerate brackish water and can be found in estuaries.
Notable Families
The order Ophidiiformes is divided into several families, with the most notable including:
- Ophidiidae: Cusk-eels, the largest family with over 150 species.
- Bythitidae: Brotulas, a diverse family with over 100 species.
- Carapidae: Pearlfishes, known for their symbiotic relationship with other fish.
References
For further information on Ophidiiformes, consult these reliable sources: