Too many stars

[Jorober]

So my roommate asked me to post this here, and see what you all think. He has a 330G reef tank, and there are a ton of little star fish that have shown up in the last few months. Probably close to a hundred. He was told at a couple LFSs to put in a harlequin shrimp, but he has two sand stars, a large brittle star, and a tile star that he doesn't want to lose. Are there other options for getting rid of, or controlling these star fish? I'll include a picture of them. Thanks for your input.

 

[ludnix]

Lower the nutrients in the tank. Their population is directly reflecting the amount of available algae for them to feed on, reduce the algae by reducing the nutrients and their population will die down.

 

[Jorober]

well I'm not sure the nutrients are very high, though. I could be wrong, but my rationale is this, he feeds his fish some high protein flakes, and spirulina mixed together about every other day, and not more than they can eat in about 60 seconds. The corals he feeds once a week. He has an ASM G6 skimmer (rated for 1200G) that pulls out some crazy gunk. His nitrates are always 5 or less (usually around 2) on a salifert test, and his phospates are currently 0.04, on a hanna phosphate meter.

Now his phosphates were extremely high over the last few months (around 0.6), but when he quit using DTs phytoplankton every other day, they fell to 0.04 within a week and a half.

If I'm not looking at the right things in relation to nutrient level, then let me know. We're both constantly learning. Thanks.

 

[sufunk]

I feed my corals pretty heavy and as a result had a HUGE, almost startling population of asterina stars. There were literally thousands. When you looked at night, there would be 50 or more just on each little 1 inch frag plug and more than you could count on the glass.

I tried manual removal but that was hopeless and finally broke down and got 2 harlequin shrimp. I have a large brittle and the harlequins are pretty small and as far as i can tell, they havent bothered my brittle at all, at least not yet. I know it may happen eventually but i think the stars were starting to bother my corals since they were practically covering some of my corals at night.

I still have alot but their population has been cut at least in half by the look of it. They will definitely eat them ime but once the stars are gone, there will be nothing for the harlequins to eat and they may go after the brittle. I figured that i have so many, it will be a long time before my harlequins start going hungry. To me, it's worth the risk to be rid of the asterinas.

 

[Jorober]

<a href=showthread.php?s=&postid=15393455#post15393455 target=_blank>Originally posted</a> by sufunk
I still have alot but their population has been cut at least in half by the look of it. They will definitely eat them ime but once the stars are gone, there will be nothing for the harlequins to eat and they may go after the brittle. I figured that i have so many, it will be a long time before my harlequins start going hungry. To me, it's worth the risk to be rid of the asterinas.

How long did it take to cut the population in half?

 

[sufunk]

It's been about a month or so.

I'm not usually big on getting livestock with the plan of removing it eventually but if the need arose, my harlequins would be very easy to remove,imo. They are almost always right at the front of the glass and even when i have my hand in moving/adding frags, they sit right there and dont move at all. Unless i'm seriously mistaken, i could catch both of mine in literally 2 minutes once they eat them all the asterinas or start bothering the brittle.

 

[cdness]

send me some...

 

[ludnix]

<a href=showthread.php?s=&postid=15393334#post15393334 target=_blank>Originally posted</a> by Jorober
well I'm not sure the nutrients are very high, though. I could be wrong, but my rationale is this, he feeds his fish some high protein flakes, and spirulina mixed together about every other day, and not more than they can eat in about 60 seconds. The corals he feeds once a week. He has an ASM G6 skimmer (rated for 1200G) that pulls out some crazy gunk. His nitrates are always 5 or less (usually around 2) on a salifert test, and his phospates are currently 0.04, on a hanna phosphate meter.

Now his phosphates were extremely high over the last few months (around 0.6), but when he quit using DTs phytoplankton every other day, they fell to 0.04 within a week and a half.

If I'm not looking at the right things in relation to nutrient level, then let me know. We're both constantly learning. Thanks.

If you're getting enough algae growth to support that many stars than I would consider the nutrient level to be high. I wouldn't read too much into the readings of the phosphate and nitrate test kits, those can only test the levels of the water, not what is currently being used by algae and consumed by the stars eating the algae.

How long has the tank been running and what is the stock list? If you can't do the harlequins and must get rid of them the only option I can see is to lower their food supply by lowering the total available nutrients in the tank. Personally I would leave them be, I haven't seen any evidence to suggest Asterina stars harm corals and and they can be easily removed from the glass with a mag-float.

 

[GrimReefer82]

I leave the asterinas in my tank alone. IMO they are beneficial creatures. If they are covering the glass during the day or are covering the corals during the day then I would reduce their numbers somewhat. I like the little buggers!

 

[amkelly802]

i see the same thing in my tank, but i find that most of them are out during the night and dont seem to bother anything.. no problems here, and my friends are always amazed at how many there are

 

[Jorober]

Well his phosphate level only came down a week ago, and he has had some big algae blooms up until now. maybe as the phosphates remain down we'll see the algae decrease, thus lowering the available food for these stars. then they should decrease in number as you're saying. If not then he'll probably try a harlequin shrimp.

This tank is 330G, with a total system capacity of about 450 gallons. It has been up for over a year now, but he has had a reef tank continuosly for the last four years. Each time he upgraded, he reused all the contents from his existing tank when he set up the new one, and we always did the tank exchange within a matter of a couple hours to limit die off of bacteria and microorganisms. New rock and sand were added each time, but he never got rid of any existing rock. There are about 35 fish in it, including two blue jaw triggers, and a pink tail trigger. These have never bothered his cleaner, fire, or peppermint shrimps before, so we THINK they wouldn't bother a harlequin, but who really knows until you try.

 

[Jorober]

Thanks for all your input. It's been great. Keep it coming!

 

[rhdoug]

If you keep a tank for several years you will see populations of many different creatures rise and fall. I would bet after a few months they will exhaust whatever food source they are eating and they will thin out on their own. I personally would enjoy them while they last, unless of course you are seeing some kind of damage from them.

 

[briangg57]

<a href=showthread.php?s=&postid=15393929#post15393929 target=_blank>Originally posted</a> by GrimReefer82
I leave the asterinas in my tank alone. IMO they are beneficial creatures. If they are covering the glass during the day or are covering the corals during the day then I would reduce their numbers somewhat. I like the little buggers!

I agree totally, No one would look at my tank and even say that I have the slightest algae problem. My tank has VERY LITTLE algae and I thank my lucky stars for that!!!