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Beauties of the Genus Pseudanthias

Anthias (subfamily Anthiinae of the Serranidae family) are perhaps the most consistently colourful and attractive of all reef inhabitants. Almost all species exhibit stunningly bright and patterned forms, some of which are amongst the most iconic and ubiquitous amongst reef imagery (for example, the Lyretail Anthias, Pseudanthias squamipinnis, which can be regularly seen in reef photography). Amongst these, the most easily recognisable are the members of the genus Pseudanthias - the imposter Anthias.

Almost all members of the genus exhibit strong sexual dichromatism, or in plain English, a marked visual difference between the adult genders. All are sequential protogynous hermaphrodites, meaning they commence life as sexually immature females, but given appropriate social cues, can transition to various states of the male gender. There is four typical states in the life history of any member of the genus: initial/submissive female, dominant female, subdominant/initial male, and “supermale” or terminal male. Also, many species exhibit strong sexual physiological differences; many of the dominant males will exhibit an enlarged dorsal filament (usually from the second or third dorsal spine) for example.

These fish are common in the aquarium trade, however many species are considered to be too difficult for captive life due to several factors. Many of the species are deepwater pelagic swimmers in nature meaning they come from open water at significant depths - in excess of 200m in some species - and so seldom adapt to the conditions of the typical aquarium. Part of the problem also comes from their diet being strictly pelagic zooplankton - tiny marine crustaceans that swim freely in the water. Their metabolism is necessarily fast and so they spend much of their time actively feeding from the water column.

On display here are some of the more seldom seen of the genus. This is usually because of their remoteness of range and depth. Some of them are only ever seen by closed-circuit divers in the right place at the right time, hence the fairly recent discovery of several of the above. To my mind, they’re also some of the most gorgeous of the genus - one of the most beautiful groupings in the sea.

1. Pseudanthias aurulentus
2. Pseudanthias calloura
3. Pseudanthias charleneae
4. Pseudanthias elongatus
5. Pseudanthias leucozonus
6. Pseudanthias randalli
7. Pseudanthias taeniatus
8. Pseudanthias ventralis hawaiiensis
9. Pseudanthias ventralis ventralis
10. Pseudanthias sheni

Most of these exhibited are of the terminal male phase, which is almost ubiquitously to the genus the most colourful and extravagant of the colour forms. Males are the masters of harems - sometimes numbering into the many hundreds - and have an incredibly involved social structure under their watch. This can often lead to violent disagreements, providing a pathway for succession by subdominant specimens when a dominant is injured or killed.

Anthias. Some would say that a reef just cannot be as exciting or vibrant without their stunning and intense presence.

(via moreanimalia)