Do Feather Dusters shed?

[pepetj]

I have two wild caught "giant" or "Magnificent" feather dusters, most probably Sabellastarte indica. They receive ZooPlex as main food but they also catch their share of in-tank pods (I collect them from an Intertidal Reef zone once or twice a week for my Mandarin Dragonet pair).

Last week both stop displaying their feathers so I got worried. Three days into this behavior I noticed they were still alive but seemed to have lost their feathers. Today I noticed the feathers are growing back as they venture to display them.

Do Feather Worms shed their feathers? There seems to be little info on their life cycle and behavior in captivity.

Here are a few pics to show my observations: (Placed in tank December 2010; Monday Feb 8th first day they were not displaying their feathers)

Pepetj
Santo Domingo

 

[pepetj]

more pics (I only can upload one pic per post)
Feb 11 2010 (the showed this appearance since Monday February 8th). They stayed 24/7 either fully retracted or coming out like this (without a single feather in them=

Pepetj
Santo Domingo

 

[pepetj]

and today they're like coming back (growing back their feathers).

Pepetj
Santo Domingo

 

[GoingPostal]

That's usually a sign they aren't getting enough food to sustain them, they will grow back a smaller crown.

 

[sjfishguy]

I agree with postal, usually means something is wrong. Although they can survive as they grow a new crown, when they lose their crown it means they are not happy

 

[pepetj]

As far as measurable parameters I found no problems. I might need to increase light time (actually in 12 hours) but I have no clue what could have happened here. I noticed other species of Feather Dusters are actually reproducing.

Mg and Ca are at the high end and as expected for Coralife salt mixture (I haven't had the need to use my Kalkwasser) (Mg Seachem test; Ca API test);

Specific gravity 1.026 (floating glass) 53.5mS/cm (calibrated PinPoint Salinity Monitor);

pH 8.1-8.2 (three point calibrated Oakton ecoTestrpH2) (I have experienced two episodes of pH down to 7.9)

Alkalinity: 7 to 9 dKH (API, Hagen, Tetra Test). I supplement with Instant Ocean's SeaBuffer to raise it when it falls down to 6.5.

Nitrates and Phosphates: almost negligible (I have a DIY Algae Turf) (Nitrates with Seachem test; Phosphates with API Test)

My tank is experiencing a red slime algae bloom (cyanobacteria) that I am not intervening with (for the moment).

Pepetj
Santo Domingo