Starfish, A Page All About Them

Lynden

a "fish hater"
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I see lots of posts recently asking about starfish, that is, what they eat, compatibility, et cetera. This topic will therefore, on the request of Steelhealr, give a quick rundown, by genus, or "type", of the most commonly purchased/encountered in aquaria stars, giving such details as aquarium survivability, hardiness, and dietary needs/compatibility, in the classes Asteroidea and Ophiuroidea (brittle stars). I will refer to both brittle stars and asteroid stars as "starfish".

I will also include a simple 'rating' for each star. A '*****' indicates a very hardy and easy to feed star, whereas a '*' indicates that few people have had any success keeping them for periods over a few months. Also a 'C' indicates that the star feeds on visible ornamental fauna and is thus "un-reef-safe".

All starfish (and all echinoderms for that matter) can go a long time without food. I suspect that most aquarium "for no reason" deaths result from lack of food, leading to the star slowing to a stop over a period over a few months, followed swiftly by death.

First a general description.
All echinoderms follow a pattern of penta-symmetry (five sides that are all the same). They move via a system of tube feet: the thousands of tiny sticky pads under the animal. Their vascular system is hydraulic. There is no circulatory system and all gas exchange is accomplished by simple diffusion.

Starfishes typically extrude their stomachs to envelope food and digest it externally, whereas urchins have five strong teeth that are self-sharpening and used to grind apart foods.

A note often brought up is acclimation times. I cannot speak with any experience on this subject as my brittle and choco chip (got them at the same time) both fell over in the tank after fifteen minutes and they lived until the tank crashed (due to outside causes) several months later. It would be safest to drip acclimate the animal over a period of an hour. Use a bucket, and place the star on a piece of live rock so that it doesn't need to be detached from anything when it is ready to be placed in the tank.

Selecting a healthy specimen is important. An active animal, with no obvious infections/infestations, or lesions on the skin, is good. A missing arm need not disqualify a specimen from purchase, unless the injury site appears to be necrotic. If the store will do so, ask them to place the animal on it's back, and see if it's able to right itself; specimens that cannot may lack the stamina to be taken to a new environment.

On a similar note keep water quality as high as possible. That means biweekly water changes of fair proportions (25% in my case), no ammonia/nitrite, and as little nitrate as possible. While it is true that many stars can be hardy, it is best not to take chances, especially since changing water isn't much work.

Lastly, though I consider this article a good source (though decidedly short), it is always best to research from many different sources. Do read the links provided if you are looking at purchasing any starfish.

Species profiles (Asteroidea)
Protoreaster
(such as chocloate chip, and red general); *****, C

Red General, P. lincki - photo courtesy of wikimedia.org

Chocolate chip, P. nodosus - photo courtesy of wikimedia.org

Size: Chocolate chip stars can occasionally hit 8'' if given time and adequate food, and red generals can grow even larger. These stars do not need as much room as similar sized microfauna eating stars do, but I would suggest nothing short of a 75 gallon for a full grown red general, and at least 55 gallons for a full grown choco chip. With that said, they can be kept in slightly smaller quarters (though not ideal) and baby sized ones can be kept in tanks appropriate to their size, even nano tanks for a time.

Feeding: these stars are voracious omnivores. They will eat anything they can catch, even fish from time to time. It would be wise, therefore, to include them in fish-only tanks with large, wary fish such as angels or Anthias.

Feeding should consist of offering 'bite' sized pieces every other day or so. Suitable foods are silversides, shrimp, squid, clams, and anything other sea-faring food fit for human consumption. Good ways to offer the food is to shove it into a rock crevice; put it in the same place every time, and the star will learn to go to that place when hungry. Nori can also be offered.

Compatibility: large, nippy fish, such as Thalassoma, Coris, and Novaculichthys wrasses, plus the largest of benthic triggers and puffers, are all capable of killing a Protoreaster. Avoid housing the two together unless both are very well fed and the fish was purchased at a young age. Apparently very few predators will eat these stars, however. (1)

Archaster, Astropecten, Sand sifting star; ** - photo courtesy of liveaquaria.com


Size: these guys can reach a foot in diameter, though they will probably remain smaller. They need a wide, shallow (as in vertically) tank of preferably a few hundred gallons. Need large amounts of sand and little rock, and can denude tanks of microfauna when large.

Feeding: the hardest part. Will eat anything alive in the sand bed, and they tend to be hyperefficient, clearing even seemingly large tanks of food in a few months. It remains to be said if they could eat food placed in the sand bed, but perhaps it would be a good idea to overfeed the tank on a regular basis to breed prodigious amounts of microfauna. Of course keep up with the water changes.

These animals are hardy for the most part, the only real concern is feeding. Highly compatible with most other livestock, but large wrasses and large benthic tetraodonts are capable of digging up and killing these stars. Shouldn't be too much of a problem.

Fromia (such as peach star, Indian star, marble star); *** - photo courtesy of liveaquaria.com


Size: Fromia are among the smallest of ornamental starfish and as such are much easier to provide for than most. According to liveaquaria, the pictured species only reaches 3'' in diameter. (2) Should have a tank of at least 40-50 gallons with as much live rock as is aesthetically acceptable (for one adult specimen).

Feeding: eats tiny creatures and algae. It will help the star if one were to allow "pest" algaes to grow, as these will harbour an enormous amount of 'pods and other microfauna. Still, it is best not to have any other microfauna eaters in the tank and these would include mandarins, fairy wrasses, pipefish, etc. Though if one attached a refugium to the tank, it would probably work.

Compatibility: large puffers, benthic triggers, and large wrasses may try to eat this star. The star itself typically leaves ornamental animals alone.

True Linckia (such as the blue star); ** - photo courtesy of wikimedia.org


Size: these stars can become quite massive, sometimes (but very rarely) reaching 15'' in diameter. A medium to large specimen, about 5-6'' in diameter, will need a large tank with a huge amount of live rock. A full-grown specimen (13-15'') should be provided with nothing short of a one hundred gallon tank, with as much rock is as aesthetically acceptable. I have heard the minimum for these species varying between seventy five to several hundred gallons.

Feeding: as above must be given a large amount of live rock. The true feeding needs of this starfish are poorly understood, but it would appear they are largely bacteria eaters, undoubtedly with some algae and microfauna included. Therefore the very best way to keep them fed is with live rock and slight overfeeding of the aquarium, but feeding can apparently be supplemented, if one uses very tiny foods (such as mysis fragments or brine shrimp) and makes absolutely sure that the star grasps it. I suspect that this alone will not keep them well fed forever, as one point being they are often unreachable in the reef tank. (5, contributed by tat2life)

Linckia are often damaged in collection, and it would appear that up to ninety-five percent of them can be damaged beyond recovery. (3) It is very important one selects a healthy specimen; one that is active and rigid, with no sunken areas or obvious infections/infestations, are most important. An otherwise healthy animal that is missing an arm or two need not be disqualified from purchase.

Acanthaster (Crown-of-Thorns); ****; C - photos courtesy of wikimedia.org




Size: these beautiful animals can hit 15'' across. As such, needs a large tank, nothing under 90-120 or so gallons, preferably long, wide and shallow. Should have some live rock, but the star may strip it clean. Good for tanks without corals or slow moving inverts.

This is the star that has, freed of predatory pressure and had their larvae overfed by man, "destroyed our reefs"; by all means buy one if you want. Is very pretty, but handle with great care. Do not ever touch the spines.

Feeding: prefers hard corals, especially SPS, but will also accept smaller meaty foods and algae.

Compatibility: it is unlikely that an aquarist will have anything that preys on this star. Harlequin shrimp, Triton Trumpets, and Napoleon Wrasse are all predators in the wild. (4)

Asterina, ***** photo courtesy of pirx.com


Size: Very tiny, typically as hitchhikers. I saw one in my tank that was perhaps 3/4'' across, see-through with red spots. Often breeds prolifically.

Feeding: usually eats algae, sometimes corals. Will do well with plenty of rock.

Compatibility: often cultured as food for harlequin shrimp. Will likely be chomped by fish with crushing or sharp jaws.


A note on other Asteroids:
Could be treated as with Fromia if small, as Linckia or Archaster if large. Do make sure the one you are buying is not a predator.



Ophiuroidea

Brittle Stars, *****
- photo courtesy of seasky.org


photo courtesy of wikimedia.org


photo courtesy of King County Natural Resources and Parks


These animals are among the best scavengers for a reef tank. They do not bother living things generally, but green brittle stars may learn to capture live fish. In direct contrast to asteroid stars, brittle stars can move very quickly, throwing themselves about with their long arms. May spend time hidden.

Size: highly variable, many come as hitchhikers on live rock, others can be quite large. They can easily be kept in nano-tanks, and to be kept in groups the larger specimens should be provided with ten gallons an individual. Minimum tank size, in my opinion, is ten gallons, and the smallest ones can be kept in tanks as small as a gallon.

Feeding: simplicity in itself, brittle stars accept leftover fish foods without hassle. It may be a good idea to directly feed the largest ones with krill or squid pieces.

Compatibility: Can be attacked by large wrasses, puffers and benthic triggers. If the star has a good shelter, the chances of predation are reduced. Arms will regrow if broken.


Sources

-http://www.wetwebmedia.com/seastars.htm
-http://en.wikipedia.org/wiki/Asteroidea
-Marine Fish and Reef USA, "STARSTRUCK!" by Jeff Kurtz, pages 100 and 101
-http://www.liveaquaria.com/product/scateg.cfm?pCatId=528
Written by Lynden B.
I give permission for anyone to copy this article in whole or part for any reason, on the condition that the sources are credited.
 
great post man, but there are ways to feed the True Linckia, you can either stick frozen food on the glass right next to it, stick food on the rock next to it, pick it up and put food in your palm then place the star on your palm... underwater of course. or mix frozen food with a tiny bit of water and use a syringe to squirt the food onto his legs, usually when there looking for food they will have 1 leg raised up.. on the glass there leg is raised out of the water so its really easy to feed. u will see when u squirt its leg the thousands of suckers/tenticles on its legs move the food into its mouth. if your going to do it any other way u only need a piece of food the size of a baby finger nail. but they are alot of hassle trying to feed them because most the time there behind filters or under rocks hiding away so u cant feed it at certian times, oh and they only need fed once a week at the most. they are kewl stars but the success rate of keeping them in tanks isnt very high at all.
 
Reading. WTG. Frank

Thanks Lynden! Much needed!
Heh, thank you. I hope more people can continue adding to this. :)

great post man, but there are ways to feed the True Linckia, you can either stick frozen food on the glass right next to it, stick food on the rock next to it, pick it up and put food in your palm then place the star on your palm... underwater of course. or mix frozen food with a tiny bit of water and use a syringe to squirt the food onto his legs, usually when there looking for food they will have 1 leg raised up.. on the glass there leg is raised out of the water so its really easy to feed. u will see when u squirt its leg the thousands of suckers/tenticles on its legs move the food into its mouth. if your going to do it any other way u only need a piece of food the size of a baby finger nail. but they are alot of hassle trying to feed them because most the time there behind filters or under rocks hiding away so u cant feed it at certian times, oh and they only need fed once a week at the most. they are kewl stars but the success rate of keeping them in tanks isnt very high at all.
Thanks, updated. :good:
 
thanks, when i upgrade my tank i want a star, but dont know which one to get... hopefully this will help.
 
There is some more info coming in a while... pending approval. It will be a lot bigger and better when complete.
 
Not yet, been too lazy. Some of it is conflicting, so I need to find a way around that.
Consider the sources and which is most likely to be correct. If possible look at other recommendations/information from the source and look at the accuracy of these further items. If the worst comes to the worst, post the two statements and let us know the sources, then the reader can either advise of which seems the most appropriate, or at least make their own mind from information provided.

Sometimes it is better to just give two conflicting ideas than try and decided which you think is going to be the best.
 
Added a couple edits for links and pinned. Moving forward we may index this topic in the future to remove pin-clutter but since there are few for now it will stay :). Nice work Lynden :good:
 
Here is some extra info, coming from a book Andy owns, sent to me via PM. It explores starfish and brittle stars with a brief word on crinoids (sea lilies). Keep in mind that much of my info in the first post comes from a different author(s) entirely, explaining several points of conflict. It is best to take both into account when deciding what to believe.

The below information is from Marine Invertebrates by Ronald L. Shimek, Ph.D 2004; pages 364 to 391

The book is somewhat brief, but gives some guidance on the stars and their diets.

Acanthaster planci

Crown of Thorns

Gets to 18", not suitable for a coral aquarium as it is infamous from its ability to eat corals. Most in the hobby only reach a few inches across, but are still enough to do damage to both corals and an unwary aquarist.

Fromia spp. (F. monilis, F. milleporella, F. ghardaqana, F. nodosa) The marble stars.

None of these fish are considered suitable for the aquarium. Those that acclimatise to a tank will usually starve to death over the coming 12 months. It seems a large part of the diet for all of the Fromia spp is live sponges, and each one would normally range over a far larger area than found in our tanks.

Iconaster longimanus Double Star

The diet of this star which grows to 3.5" (9cm) is somewhat unknown, though it is believed it may be a scavenger. It seems a 100 gallon is the minimum size to offer the area needed, but even then it often dies within a few months from malnutrition. One best left on the reef.

Linckia laevigata Blue Linckia

Grows to about 16" (40cm). Natural diet is not known. Appears to eat and accept meaty foods but seldom survives past 18 months, seemingly dying of malnutrition. It is certainly possible to keep them a year, but 2 seems rare.

Linckia multifora Spotted Linckia

Grows to 4 in (10cm) and is suitable for most aquaria of 100 gallons or over. They seem to be able to persist indefinitely (unlike most sea stars). May be attacked by crabs, hermits and some fishes.

Astropecten spp. andLuidia spp; Sand Sifting Stars

Maximum growth expected is 12", though obviously not all species will get there. Large tanks of 100 gallons or more are recommended before even thinking of attempting to keep. These feed on sediment infauna and have a habit of stripping a sand bed dead very quickly before starving to death.

Oreaster reticulatus Caribbean Cushion Star

Grows to 12" but is a inhabitant of sea grasses where it feeds on sponges. In captivity it will eat sponges and other echinoderms, but seldom gets enough nutrition. Also, this star is too inflexible to be able to navigate rockwork. Has few predators.

Pentagonaster duebeni Red spot star

Grows to 6". This sub-tropical species feeds on encrusting sponges and bryozoans. It will require cooler water with the temperature around 21 to 25 C (70 to 77F). Dietry habits in the tank are poorly known and it may consume SPS and or low soft corals.

Protoreaster lincki and P. nodosus Red Spined and Chocolate-chip stars

Former to 12", later to 5". Reported to feed on sponges in the wild and are a risk to sessile inverts in the tank. Most in the tank die of malnutrition. The nodules on these stars make them a target for some Tetraodontids to nibble off.

Choriaster granulatus Doughboy Star

To 20". Requires large tanks, of 200 gallons or so. Will readily eat corals, but is hardy and can be kept in a non reef tank. Unlikely to have any enemies in the tank as an adult (unless you keep Triton's trumpet snails.

Culcita novaeguinae Cushion star

Up to 12". Needs a tank of 100 gallons and will need corals to feed on, so not a great choice for many people.

Astroboa nuda, Astrophyton muricatum Basket stars

Grows to about 24". Will need at least 300 gallons to fully expand arms. Typically starve in captivity and should not be kept with most reef fishes to prevent predation on the star. These need a constant supply of zooplankton at night.

Ophiactis spp. Spiny Brittle Stars

Up to 6". These are good aquarium scavengers that should thrive in tanks of 50 gallons or more. These stars may be at risk from crustaceans in the reef, and in turn there is a risk of them consuming small sleeping fishes.

Ophiarachna incrassata Green Brittle Star

Grows to 20" and predates on a number of animals. It is one of the most voracious inverts in captivity and as such has no place on a reef. Has been documented to eat firefishes, damselfishes, mandarinfishes, blennies, small gobies, cleaner wrasses, cleaner shrimps and crabs. However, if a tank of 100 gallons or more is dedicated to the care of the star it will make a good pet.

Ophiocoma spp.

Up to 8". Will require a tank of at least 50 gallons. These stars are very good at hiding during the day and then coming out to forage at night. normally they disturb nothing on their nocturnal forays for food, but occasionally a stationary or "sleeping" fish will be too much temptation.

Ophioderma spp.

Up to 12". These good scavengers are gerenally fine for a tank of 50 gallons or more, though they have been seen climbing gorgonians. This may be to eat the polyps, but Shimek believes it is more likely they want to suspension feed in the current the gorgonian has found.

Ophiothrix spp.

Up to 12". Has a poor survival rate in captivity and little is known of the natural diet. They often found on and near sponges, but it is unclear whether they actually eat the sponge, graze on it, or filter feed on their own. They do, however, die in captivity.

Crinoids Feather stars

These beautiful creatures extend up to 24" across the arms. Unlike most suspension feeders these fish react differently to each molecule that touches the tube feet. This selective feeding style means getting the star to eat is somehwat difficult because if the star doesn't like it, it will just ignore it. At this point in time there is no known perfect feeding supplement, so any stars in captivity are almost always going to die of malnutrition.
 
Don't forget some Asterinas feed on zoa.

http://www.zoaid.com/gallery2/main.php?g2_itemId=1426
 

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