Longfin Damselfish is a fish from the Western Atlantic with the scientific name Stegastes diencaeus.
It belongs to the Pomacentridae family and sometimes appears in aquariums. This fish has a helpful relationship with Mysidium integrum shrimp.
The Mysidium integrum shrimp give nutrients to algae that Longfin Damselfish eat while the fish protect shrimp from enemies.
Adult Longfin Damselfish lives in protected coral and rocky reefs near shorelines.
It’s territorial and aggressive by nature. Hence, you need to be cautious while adding it to reef aquariums.
Longfin Damselfish Interesting Facts
- Longfin Damselfish have a mutual relationship with Mysidium integrum shrimp, exchanging protection for nutrients.
- These fish can be aggressive and territorial, making them a challenging addition to reef aquariums.
- Young Longfin Damselfish display bright yellow coloring with blue lines, while adults are dark gray-brown.
Longfin Damselfish Habitat
Longfin Damselfish is found in the Western Atlantic, from southern Florida (USA), across the Bahamas, and the Caribbean Sea.
Its habitat includes areas like Antilles, Yucatan, and Venezuela.
Longfin Damselfish lives in marine environments near coral reefs.
It doesn’t migrate and prefers a depth range of 2 to 45 meters, though it’s usually found between 2 to 5 meters deep. This species thrives in tropical conditions.
| Water Temperature: | Unknown |
| Water pH: | Unknown |
| Water Hardness: | Unknown |
Longfin Damselfish Physical Characteristics
Size: 4.9 inches (12.5 centimeters)
Longfin Damselfish grows up to 4.9 inches (12.5 centimeters) long. It has 12 dorsal spines, 15 to 16 dorsal soft rays, 2 anal spines, and 13 anal soft rays.
The anal fin is long and pointed, extending beyond the tail’s base.
Adult Longfin Damselfish are dark gray-brown with blackish scale edges. They sometimes have a yellowish tint on their head and back near the dorsal fin’s top part.
They also have a small black spot near the upper base of their pectoral fins.
Young ones are bright yellow with two blue lines that run along their head and break into spots beneath the middle of their dorsal fin.
They also have a large blue-edged black spot at the base of their dorsal fin, centered on the last spine.
Longfin Damselfish Reproduction
Longfin Damselfish lay eggs to reproduce. During breeding, they form distinct pairs. Their eggs stick to surfaces underwater and don’t float around.
Male Longfin Damselfish protect the eggs and help provide oxygen to them by aerating the water near them.
Longfin Damselfish Scientific Classification
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Family: | Pomacentridae |
| Genus: | Stegastes |
| Scientific Name: | Stegastes diencaeus |
| Also Known As: | Longfin Damselfish |
| Conservation Status: | Least Concern |