ID and some info on little red things

[PTR18482]

Got some new live rock and about a day later noticed this little red thing, looks like a sort of snail but has no shell, soft red colour. A few days later counted around 12 of these little red things and one bright orange one with a white spot on its back. They spend most of their time on the rocks or on the glass. Very small no more than 5-7 mm long, also noticed that when not on glass almost appear to have little wings and glide on the current, as when they are on the rock they are attached at the bottom and just sway with the current?
Would just like to know what they are and what they do :?:

Thanks
Peter

 

[Len]

Any chance you can get a picture of this? It's tough to say. Sounds potentially like a flatworm or nudibranch of some sort, but that's a guess at best.

 

[PTR18482]

Here are some very dodgy pics, I coudn't quite get to him and the camera is flat.

the first pic is from the front of the tank and he/it is in the bottom right corner of the tank, the second pics is from the side of the tank as close as i could get to "it"

hope this helps,
thanks
Peter

 

[PTR18482]

stop, rewind, switch that, ok

pics are the other way around

thanks
Peter

 

[Anonymous]

REALLY hard to tell from those pics but the second one looks like the silhouette of a nudibranch.

 

[investigator1]

Ok it's probably one of these three:

1) Aplysia punctata

2) Flabellina pedata

3) Berthelina edwardsi

 

[PTR18482]

Thanks for that,
probably closest to number 2)Flabellina pedata, do they have a juvenile stage where they are only one colour?
What do these things do?

Thanks
Peter

 

[Len]

They're that color from birth, but some are a bit more red (or purple) then others. They are hydroid eaters but won't touch fish or corals. To be safe though, I tend to remove these mystery critters and put them in the sump or seperate tank for observation.

 

[investigator1]

Flabellina cynara
(Marcus and Marcus, 1967)
Order:
NUDIBRANCHIA

Suborder:
AEOLIDINA

Family:
Flabellinidae



DISTRIBUTION: Pacific coast of Central America

PHOTO: Playa Mismaloya (Bahia de Banderas), Mexico, 40 feet, 7mm long. Photos: Alicia Hermosillo


This species is commonly called the 'Swimming Cynara', and to quote Hans Bertsch:
"Most memorable is the swimming behavior of Flabellina cynara, which was so brilliantly illustrated by Wesley Farmer in his 1970 paper, "Swimming Gastropods (Opisthobranchia and Prosobranchia)" (The Veliger, 13: 80-83). The slug uses back-and-forth strokes of its whiplike cerata to propel itself through the water. The cerata gently curl forward in a loosely coordinated flowing movement, pause, and then whip backwards in a simultaneous power wave. The rearward flipping of the cerata is the propulsive stroke. Swimming up into the water column may allow the animal to hitch a ride on the water currents, aiding its escape from a predator or its search for prey or a mate".

Its body is deep pink with white spots. The long, thin cerata, are a translucent salmon-orange, with white speckling. They have a subterminal purple ring and a creamy white tip. The border of the foot has a rich purple marginal line. The translucent cephalic tentacles have a distal purple blotch. The the basal half of the lamellate rhinophores pinkish, and the upper half are creamy white with a subterminal purple band. Maximum body length between 40-50 mm.

Reference:


Marcus, Er, & Marcus, Ev. (1967) American opisthobranch mollusks. Part 2, Opisthobranchs from the Gulf of California. Studies Tropical Oceanography, Miami, 6(1-2): 141-256. (Figs 1-95)