Black NudiBranch-Friend or Foe?

Macimage · #1 12/20/2007, 08:21 PM

Hi,

My tank has been set up for 5 years and tonight I caught what appears to be a black nudibranch on the glass. I took a few photos, but they are not very good. He has two antennae and here are a few photos:

The two antennae are on the right side. It's black with tiny white specks/spots.

Should I banish it to the sump or put it back in the tank?

Thanks!
Joyce

kar93 · #2 12/20/2007, 08:35 PM

I dont know what it is but if it was me id put it in the sump to be safe

Swanwillow · #3 12/20/2007, 08:40 PM

if its been in the tank for 5 years.....

Aquabucket · #4 12/20/2007, 09:43 PM

Nudis have very specific diets. I am just taking a guess here but yours appears that it may feed on black sponges. In most cases if it was a coral eater it would resemble the type of coral it feeds on.

Macimage · #5 12/20/2007, 10:04 PM

Yes, I would think that if it's been in there this long, it would be ok.

I've lost almost all my small fish and can not put any gobies, anthias, etc. in as I think I have a predator, however, I don't think this nudi (around 1" long) would bother fish even while they sleep. It moves pretty fast but I don't know if it will bother sleeping fish?

I worry that if I put it in the sump that there may not be the type of food/conditions that it requires. I don't want to kill it if it is harmless.

Joyce

boomsticks · #6 12/20/2007, 10:07 PM

IMO Probably just a harmless algea eater....but it looks like its tasted blood! AAAAAAAAAAA

Aquabucket · #7 12/20/2007, 10:09 PM

Many nudis graze on sponges or corals. I have never heard of any that feed on fish.

Do you have any black sponges in your tank?

Swanwillow · #8 12/20/2007, 10:09 PM

one way to find out.
Set up a little ten gallon. Put it in, and a small $5 fish.

enjoy.

pagojoe · #9 12/21/2007, 01:34 AM

It's a nudibranch, and as far as I know, it should feed on sponges. It must have ridden in on something more recently than 5 years ago..? Most nudibranchs have short lifespans, and I'd be very surprised if this species is an exception. I'll be interested to hear what Leslie thinks about it. The most common black nudibranch is Dendrodoris nigra, and Dendrodoris fumata can look almost just like it. The little white specks on yours, the rhinophores, and the bump in the middle remind me of Hallaxa indecora, although it should be brown rather than black. The gill looks to be positioned more like the Dendrodoris species.

http://www.seaslugforum.net/factsheet.cfm?base=dendnigr

http://www.seaslugforum.net/display.cfm?id=10413

Cheers,

Don

pagojoe · #10 12/21/2007, 01:35 AM

It definitely won't eat fish.

Macimage · #11 12/21/2007, 11:53 AM

Hi Don,

Thank you for the links

!!!

I put it back in the tank last night before I went to bed, as I was worried the bucket water would get too cold overnight.

I think it looks quite a bit like the Dendrodoris nigra. I bought some small frags last month from other reefers at the Ventura frag swap. There was one 3-4" polyp rock that it could have been hidden on.

Thanks again!
Joyce

LeslieH · #12 12/21/2007, 12:11 PM

It certainly could be either D. nigra or fumata. One way to tell is by looking at the gills - if there are about 5 large bushy ones in a circle then it's D. fumata; D. nigra has about 10 small ones in an U or incomplete circle. Otherwise both species shows the same variation in color. They are thought to eat small sponges which hide in crevices or on the underside of rocks. It's quite likely it was hiding on the frags you bought last month.

Macimage · #13 12/21/2007, 07:41 PM

Thank you Leslie!

It appeared to be eating the algae on the glass. It was fun unexpectedly finding a new critter and I appreciate the links, id's and information.

Joyce

greenbean36191 · #14 12/22/2007, 02:26 PM

It may be cruising the glass, but if it's tasting algae then it's starving. All nudibranchs are exclusively carnivorous.

Macimage · #15 12/22/2007, 10:43 PM

Greenbean-Will it eat left over fish food such as mysis and cyclopeeze? A few others have posted that it feeds on sponges, which I do have in my tank, so I hope that is the case.

Joyce

LeslieH · #16 12/22/2007, 10:44 PM

No, it's a specialized predator and will only eat a certain type or types of sponges.

Macimage · #17 12/24/2007, 05:38 PM

Thank you Leslie. I have blue sponges in the tank and a rock in the sump that is covered with white sponge that I will move into the display tank in the hopes it will eat it.

Joyce