To many Brittle Star fish!!!

cpannell

cpannell

New Member
I have a 125 gallon tank with live rock. After it being up about 3 months I noticed to my excitment that I had a very small brittle starfish on the glass in the substrate. As the months have gone by I have noticed more and more of them. Recently I was taking some of this substrate out to jumpstart a smaller tank. I took a single cup of substrate and just for kicks spread it out over a 8 x 5 glass casserole dish. To my amazement I found 30+ small specimen. As best I can tell they are brittle star fish. They are very pale and none of the bodies are bigger then 1/8" with legs they aare about the size of a quarter to fifty cent piece.
Here are my questions.
First is this a bad thing? I am worried that they could dominate my tank.
If it is a bad thing what are my options? Is there a kind of fish that would feed on them?
What if anything have I done to cuase this? Am I over feeding? Feeding the wrong thing?
My population is the following.
Clownfish
Neon Dottyback
Foxface
Powderblue tang
Blue Tang
Majestic Angel (adult)
Pygmy Angel
Two cleaner shrimp
Snails and Small Crabs
Your help is greatly appreciated.
Cpannell
 
clarkiiclo

clarkiiclo

Active Member
You are talking about brittle stars right? Not the little tiny stars that eat off the glas and stay about 1/2"? If they are brittle stars that is ALOT. I had 2 large brittles and I had to get rid of them. They kept trying to eat my huge condy.
They will grow fast and eat everything they can get ahold of. I dont want one even in a fuge.
 
ophiura

ophiura

Active Member
Do they look like this?

(From my website at http://home.att.net/~ophiuroid)
If so, this is perfectly normal and you are doing nothing wrong and probably lots right! Perhaps you are overfeeding a touch...but these are the sort of critters that help with the excess food.
The little brittlestars are usually maybe the size of a nickel or quarter (including the arms) and are white? This is Amphipholis squamata, a common and highly desirable hitch hiker and member of a sand bed. They will NOT get larger than this, and do a great deal to clean up little particles in the sand. They are a self fertilizing hermaphrodite, that broods its offspring. If you get one, you will get many. And if you have LR, you got one.
Many people want more so you could probably sell them.
As for larger brittlestars, well, I would disagree that they all cause such trouble. ClarkiiClo - what did you feed your brittlestars? And what color were they?
I have not heard them eating anemones. They may very well take shelter around them, and they may very well be attracted to an unhealthy anemone, coral, etc. But those that are predatory eat things like fish and shrimp...two stars eating a heatlhy anemone is new to me. It is just not really a normal food item. So if it happened, I would like to hear more about the behavior you saw, and how often they were fed and to try and figure out what species it was.
The green brittlestar is a known predator in the wild but I would say do little in captivity considering the number of people who keep them. Still, it is a potential issue, but most people have no issues with them...they certainly will not eat everything they can get a hold of. I have had quite a few starve and refuse nearly every tidbit I tried.
 
clarkiiclo

clarkiiclo

Active Member
The little brittle stars are good I agree.
As for the stars I had they were green brittle stars. They were big. Over a foot across. They were not supposed to be that big. Only 2-3" HA HA. One of my first purchases from an online store. That was a bad idea. :notsure:
They would eat anything. Krill, zoo, flakes, junk on the bottom. When I first got them I really liked to feed them by hand. They were like little elephants. I thought it was cute. Awile back I had a few large bristleworms. I lifted a rock and caught one. I chopped him in half and was getting ready to remove it. The brittle stars ate that worm before I had a chance to. It only took a couple seconds and the whole worm was gone.
I didnt think they would eat it. After that is when they started getting really agressive and trying to eat my anemone. Now this condy has a base of about 4" across and when he stands up he is about 7" tall. He isnt a little guy. He was and still is very healthy.
I would find one of them wrapping itself around the anemone. On top of the anemone not under him. I would pull him off carefully. A few hours later he would be right back on top of him.
I didnt know if the star could actually manage to eat the condy but I didnt want to find out.
Suffice to say I liked my condy more and I could get other things to clean the tank.
I stick to stars that dont get big. That way I know they cant eat things I dont want them to.
Ophiura if you look in this months picture contest you can see one of them close up.
It may give you a better ID than just green brittle star.
 
ophiura

ophiura

Active Member
Very nice pics! And those are the green brittlestar, Ophiarachna incrassata. They are known for forming "caves" by standing on the tips of their arms. Small fish seeking a nice place to sleep swim in, and bammo, the brittlestar closes down on them. Ditto with shrimp. It is hard to know if they were doing that with the anemone, or smelling food it may have eaten or what. But I will take your word for it! If any beast would be doing that, the green is the one. FWIW, they get very large indeed...probably the largest of the "hobby" species and perhaps one of the largest period.
They have very cool behavior, compounded by the amazing fact they do not have a brain. Extremely complex behaviors...so clearly, we just don't quite understand what their brain is yet.
It may not help, but most other brittlestars are not quite so voracious! :)
 
cpannell

cpannell

New Member
Thank you Ophiura. You do not know what a relief it is to know that this is not a problem.
The Picture you linked is identical to what I have.
Have to say guys that spreading out a cup of substrate in a clear glass casserole dish was an amazing event for my son and I. The number of different bugs and things we found in the water was amazing. Try it you will be awe struct.
At least I was
Cpannell
 
klongo

klongo

Member
I have a small 10 gallon tank that I use to quarantine my newcomers in. Because it's empty most of the time, I put in a couple inches of sand, a LR (all from my main tank) and all of the crabs that were eating my snails. That was four months ago. Tonight, the rock and glass of the tank are COVERED in these same white stars.
I had seen them before and put some of the sand from the small tank into the main tank hoping to get them to spread in there - but no luck. I've never seen one in my main tank!
It makes no sense to me as the sand and rock came from the main tank in the first place. What could be killing them in the main tank? Everything else in there seems to do fine.
 
bustedup21

bustedup21

Member
I would suspect that you have a fish or two that finds the little stars quite tasty. Do you have any parrot fish or a foxface?
 
klongo

klongo

Member
nope - two ocellaris, a sally lightfoot and two peppermints. I had a lemonpeel for a while, but it died over my last vacation.
 
ophiura

ophiura

Active Member
I think we may need to clarify:
The small white STARFISH on the glass and rocks are Asterina stars. They are about the size of a nickel, generally with 6-7 "stubby" arms of unequal size. These are generally grazers on the glass and rocks (of algal films, etc).
The small white BRITTLESTARS in sand and sometimes seen here and there on rocks (though I do not imagine on the glass in any number) are Amphipholis. Brittlestars have 5 very thin arms and a round central area. This animal is a detritovore, eating small bits and things in the sand.
Both of these animals reproduce in our tanks, though the brittle would reproduce quite a bit faster than the seatar.
The Q tank would be a lower predation environment, and also a low competition environment...it probably does not have hermits etc that might compete for food with them in the main tank. These animals could "bloom" like Q tip sponges to meet supply of nutrients and then die back. If they get less food in the main tank, there may be fewer of them due to potentially less uneaten food and more "clean up" critters to compete with, as well as the loss to other animals in the tank. Each tank is different in many parameters, and it is difficult to put your finger on what is "wrong" there may be nothing wrong...just one tank supports them better for whatever reason. I am sure they are in the other tank, just not in large numbers.
 
klongo

klongo

Member
Ophiura-
Thanks for the clarification. Is there any benefit to getting more of them into my main tank? I was thinking about a couple of pounds of sand trade from one tank to the other, or a trade of the rock that is covered with them. (last night it looked like the rock was covered in a mesh of them) I'm sure the 'predatoriness' of my main tank is key- I have a TON of snails and a few hermits in there keeping my sand clean.
 
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