small starfish on glass, good bad or just ugly :)?
 

I noticed this guy on the glass of my tank earlier today and had never seen him before, I have seen them at the fish shop I normally buy from but I havent brought anything new home in over a month. He's on the glass so I am hoping he is okay, maybe just eating algea? If need be I will try and locate him again if he needs to be removed, though I have had the tank set up for 4 months and never seen him before so.... thanks for any help!

If it stays that size it's probably just a mini-star. Did you get any kits from IPSF or Inland Aquatics recently? As far as I know, these fellas are detrivores.

I have literally thousands of these guys in my tank. They multiply like rabbits! I have never seen a perfectly shaped one either :)

My observations:

They eat detritus off the sand bed
They do a really good job of keeping the glass clean.
They keep my tank fairly clean as I have NO snails in it.

However, I was shown last week that in Sprungs new invertebrate book that they eat corals. Now I have never seen this, and the picture in the book is the same as the one you posted. So I don't know who to believe, but I have never seen one on any of my corals and I have about 15 SPS frags in my tank right now. Maybe Dr. Ron has some input.

Fade

Hi,

However, I was shown last week that in Sprungs new invertebrate book that they eat corals.

Well... maybe. But... consider the source of the information. :D I consider it dubious at best.

There are presumably at least a couple of species of similar appearing little stars. There are a few reports of one variety which eat zoanthids and perhaps some soft corals.

Most reports of them indicate they are harmless, and as you indicate algae eaters or surface detritus eaters.

So... watch them. If you see them actively eating a coral or such, then go on a safari to remove them. If not, leave them be and you have something else to help eat detritus and keep the glass clean.

:D

Believe it or not, that's exactly what I did and that is why they are still in my tank. I've had them in the tank for well over a year and have never seen them even on one of my corals, much less making a meal out of one. :D

Fade

I have lots of these little starfish. I have never seen them on any corals but I have seen some coralline algae disappearing in spots once and a while. My coralline grows so fast that in a few weeks you never even notice. I've had these stars for at least 3+ years with no other affects.

George

hmmm.

take a look at this thread i just started.

henry

The people at GARF have been convinced for years that these stars eat SPS.

(GARF,I know, just adding to the discussion)

Thanks guys for all the input, I think given the consensus of actual experiences and my initial observations I will keep him around until he gives me a reason to remove him which from the sound of it he never will.

Why dont they form 5 equal length legs? Fade2black you mentioned you have many and that none of them are symetirical, does anyone know why is it just one of those things?

The stars I have grow 5-8 arms, some much longer than others. I also have some with only 2 or 3 larger arms so I would say they grow a bunch of arms and split leaving some with more or less arms than others.

George

I have these stars also... got em from a substrate "sample" from my buddy. :D He has had them over 2 years. No problems to report on either side. He has alot more than me... Only possible problem so far may be that they eat some coralline algae. His tank seems to lack in this area. Not absolute the stars are the cause to this effect. I notice no loss of it in my tank... yet..
No sps or lps in either of our tanks.... only softies...

IMO... I think the stars seek out powerheads to reproduce with.
This is why they seem to miss parts of the arms...
New meaning to the saying " Love Hurts ".
:D

Yes, these definitely reproduce asexually. They probably drop an arm or two, that's why they look funny. I'ev seen them with two arms that look almost like a straight line :) Maybe my good supply of coralline algae is what keeps them reproducing like crazy! Or maybe is is the powerheads :D

Fade

Hi,

They reproduce by fission, basically they simply pull themselves apart, so each population is a clonal array.

Lotsa things go into critically identifying a starfish, folks. Basic body shape and structure certainly are a first step, but..... To get to the species level, one has to look at other much smaller characters: tube feet arrangements, ossicle shapes and distributions, presence or absence of pedicellariae, etc., etc., ad nauseum.

Bottom line, there is no way an average hobbyist is going to identify or probably discriminate between the species in this group of stars. There appears to be at least one species (from reports by Bill Capman, among others), that is predatory. However, this particular star seems to be relatively uncommon. A similar species appears to most feeding on detritus and algal films and that particular star is relatively common.

So... watch them, and if they become a problem or if you become paranoid, go on a star safari to remove them. Otherwise, enjoy the diversity they provide.

:D