Mini mollusc

[smidoid]

I've been watching these for a few weeks now, but this is the clearest picture yet... (not that clear, I know).

It's about 3mm across and looks a little like a limpet, moves very slowly - can't detect it with my eyes.



I got about a dozen of them on some LR. Neat little fellas.

On the subject of ID (just to save another thread) how do I ID a critter that I can barely see? I can see it swimming around - looks to the naked eye and the macro like a minute white tadpole - I'm assuming some kind of 'pod. It seems to have a flagellum or a perhaps cilliated tale (if I remember the terms correctly.

Since I don't own a microscope, what else can I use to get better detail?

[greenbean36191]

Are you asking about the grey blob? If so, it looks to me like an Asterina starfish, but it's hard to tell. Try taking it out of the tank and putting it in a shallow dish of water for a better picture.

As far as IDing the little guy, your options are probably either trying to look at it with a magnifying glass, sending it off to someone with a microscope, or trying to get ahold of a microscope yourself. There are just too many tiny thing that could fit the description to try to ID it without getting a closer look at it.

[smidoid]

Yeah. I figured as much. I'll check on some better images of the Asterina and see if that (those) fit. Don't really want to disturb them unless necessary.

[Nuts: GARF says they are predatory. Just my luck! ]

I can see through the macro as well as with a magnifing glass - I agree that a scope is in order.

[Penguin]

I also think it looks like an Asterina star.

GARF is in the minority in listing them as predatory. The general consensus seems to be that most species eat algae and bacteria, and are harmless. It would be really difficult to remove all of them from your tank anyway. For every one that you see there are probably 5 more hidden in the LR.

[smidoid]

I'll go with that Penguin - until I know otherwise for sure. At the size of them, they couldn't predate much more than a brine shrimp nauplii anyway!

[BubbaWPB]

I've got a few little starfish like that in my tank too.. it's hard to believe that a 3 mm starfish that moves slower than molasses in January would be able to predatorize even the baby brine shrimp....

[smidoid]

Ummm... .slower than the molasses in January... Opening seen of "Romancing the Stone" if I remember right. They are sloooooow, though aren't they!

[Ninong]

Yeah. I figured as much. I'll check on some better images of the Asterina and see if that (those) fit. Don't really want to disturb them unless necessary.

I agree with greenbean that the mysterious blurry creature in your photograph looks more like an asterinid than anything else. Your description of its behavior is what threw me for a loop. These animals, assuming this is what you have, move around on the substrate (substrate means aquarium walls, live rock, sandbed, whatever).

[Nuts: GARF says they are predatory. Just my luck! ]

What Sally Jo has posted on her website is that she has observed some tiny Asterina seastars consuming coral polyps. She has even posted pictures of what she refers to as four different 'strains.' That is what she is reporting as her observation of what she assumes are four different 'strains' of what appear to be asterinids, based on her photographs. She has even posted emails from readers who agreed with her. Many other hobbyists have stars that appear quite similar to the ones in her photographs except that theirs do not eat coral polyps.

About three years ago, I purchased a 'detritivore kit' from Inland Aquatics and it included "Stars, micro" and "Stars, miniature, brittle." The creatures they refer to as "Stars, micro" are tiny (~1cm) whitish Asterina seastars. They reproduce in my tank. Their populations fluctuate. I have not observed any of these stars eating anything other than algal film in my tank.

I have not experienced any problems with either the asterinids ("Stars, micro") or the tiny ophiuroids ("Stars, miniature, brittle") that I purchased from Inland Aquatics.

Dr. Ron Shimek discusses these in this article. Scroll down until you get to Asterinid Stars. Here is a quote from that section: "Occasionally, some populations of these asterinids have been reported by aquarists to eat either soft corals or stony corals. These coral-eating forms, perhaps different species, seem to be quite uncommon, constituting less than five percent of the various populations."

Reefs.org mentions these in their hitchhiker section.

[smidoid]

Thanks Ninong. I do tend to take everything I read with a bit of a pinch of salt until I read independent confirmation. They do move like molasses in january though. The only reason I know they move at all is by observation over several hours. I was a bit dismayed that GARF listed the Asterinas as destructive, but at this stage, I have bigger issues...

[greenbean36191]

I did some work with these guys last year and even after starvation the ones I used wouldn't eat corals. I think it's safe to say that not all of them are predatory.

[Poseidon]

I have TONS! Never bothered my corals, and I have had softies, LPS, and SPS species with no problems.

Plus Ninong says they are OK, so that is good enough for me! ;)

[smidoid]

Plus Ninong says they are OK, so that is good enough for me! ;)

Works for me Mike!