Threadfin Anthias (Pseudanthias carberryi) - Super Male

The trailing dorsal filament that gives Threadfin Anthias their name only shows up on the dominant male, grown as a visual flex once he's transitioned from female and taken over a harem — the longer and more dramatic the filament, the more established the male. It's a small fish putting a lot of energy into a very public display, which is either vanity or good reef politics depending on your perspective.

Care level: Moderate · Temperament: Peaceful, shoaling · Max size: ~5" · Min tank: 55 gal · Diet: Carnivore, small meaty foods, frequent feedings