[Adnuces]

Looking for a place to buy these online????? Has anyone ever kept them in their dsb?

[sihaya]

Why the heck do you want one? They destroy sandbeds and will likely die of starvation eventually anyway.

[Adnuces]

I only just started looking at them and while researching found that they are voracious eaters who will decimate the sand bed......unless you have a huge tank which I don't soooooo I will consider this a dead avenue....thanks for replying though...

[sihaya]

Well... I thought I'd save you some time, but it looks like you beat me to it.

[charlesr1958]

I dont know, I have two indo-pacific sanddollars that only actualy go down into the sand during the day to hide, not moving untill darkness which they then roam the surface of the sand doing a good job of turning over the top grains of sand while it eats what ever it is on the surface that they eat. I suppose it would all depend on the species. Then again, would this be considered a sand dollar? or an urchin? It is fairly flat.



Chuck

[sihaya]

Why would you think that just because they roam the surface that means they aren't ruining the sandbed? The life on the surface of the sandbed is vital to the health of the sandbed as a whole.

Also, it doesn't look like you have a sand bed. It looks like you have gravel. Gravel is another story... then you're not really keeping a DSB anyway.

But I don't know exactly what those things are. They look like sanddollars to me though.

[davepp]

I also read they would starve after I bought one. Mines been in the my 150 6 mo and going strong.

[sihaya]

I don't mean to be a kill-joy... but it can take a very long time for them to starve to death. 6 months is nothing. Your tank might have enough to sustain one for a year, maybe even two... but they will eventually starve to death. And it's never easy to say one of these is "going strong." It might *look* strong right up until the day it dies. I mean, what does a starving sand dollar look like? Does anyone know? I don't.

[charlesr1958]

Sorry, but it is sand, and is a dsb, at times, depending on where I collect my sand, the larger grains migrate to the surface which I then siphon off the next time I do a partial live sand change. The "critter" I have shown only roams the surface at night, if it is not eating detritus and is instead eating the sand infauna, I would think it would have better luck at doing so by remaining under the sand as other species do. There surely can not be alot of sand infauna running around in the open on top of the sand. And if there is, two small specimens are hardly going to make a dent in sand infauna populations, which I seriously doubt that they are actualy eating sand infauna as it is.

The species that can be found off the coast of the states would be another story, those I would not add since they do travel throughout the sandbed eating the sand infauna. I was merely trying to make a point that I think as far as sand dollars go, it would all depend on the species in question.



While the lighting may not show it, the front of the sandbed is at least 6 inches deep which tapers upwards to one foot deep at the back of the tank.

Chuck

[sihaya]

Well... we could always ask Dr. Ron, but I have a feeling I know what he's going to say...

[charlesr1958]

True, would be interesting to know if there are types of sanddollars, which I believe are related to urchins if not a true urchin to begin with, that have differing diets. I have a few sand urchins in my sump's refuge sandbed, which is also about a foot or more deep and Dr.Ron assured me that they only ate the bacteria / detritus that gets down deep, I have yet to see them unless I dig into the sand and pull them out. Probably plum sized. Well, again, I wasnt trying to suggest that any and all sand dollars are okay, just wanted to suggest that as with any genus, the members of a genus tend to have a variety of food sources. Tend to, but dont hold me to that now...lol

[sihaya]

Sand urchins? You have any pictures of those? They sound cool.

[charlesr1958]

Okay, got myself straightened out a bit now, turns out that what I have that I have been calling a sanddollar is considered more of a "sea biscuit" aka "urchin" than what is normaly thought of as a sanddollar, which I still believe are all closely related. Dr. Ron could not say much about either since there is just about nothing known on their dietary needs. I also think my success with them is strickly because of the live sand change outs that I do on a regular basis, which probably replenishes what ever it is they are eating. Something probably not readily available to do in non-tropical locations. As such, I would then of course have to advise adding any type of sanddollar to a system since it could very well damage a static sandbed or starve the critter to death.

oh, and here are some images of the "sea biscuit"



Chuck

[greenbean36191]

I doubt a true sanddollar would really destroy a sandbed. AFAIK all species feed primarily on organics and algae in the sediment, though some may eat small infauna. Most will suspension feed as well. In any event I don't think enough is known about how much territory they graze, so I think it's best for now for people to leave them in the ocean. Charles' case is obviously a bit of an exception.

More than the possible lack of food, the thing that keeps me from adding them to my tank is the fact that it's really an unnatural environment. They're generally found in large, open sandy areas where they don't come into contact with rocks.

You also need to make sure that you're getting a truly tropical species, which can be a challenge since lots of vendors either don't know or don't say where their inverts came from.

As far as the relationship between sea urchins and sand dollars, they are very close. They're both in the same class, and most people do think of sand dollars as flattened urchins. There are some morphological differences between them though, chiefly the location of the anus. In "true" urchins it's located in the center on top. In sand dollars and heart urchins it's on the bottom near the edge. Sand dollars also have cilia lined food grooves that urchins don't.

I think your animal is actually a heart urchin rather than what we usually call sea biscuits (down here at least). They're in different orders. What are generally called sea biscuits are in the same order as sand dollars and are essentially the same thing only thicker. Heart urchins are in a different order and are bilaterally symmetrical rather than being roughly radially symmetrical among a few other differences.

[sihaya]

Well, there you go... Mike has spoken.

Thanks Mike!

[charlesr1958]

Yeah, thanks! have always assumed they all were somewhat related, but at least now I know what to look for when trying to figure out which one is which, as far as a genus goes that is. Whats funny is that all these were hitch hikers as I had never intended to keep them, but they have done well for me.

Chuck

Chuck