Your asterina experiences

Salty B

Reefing newb
I was going to post this as a responce to a thread but thought it would be interesting to get everyones thoughts on asterinas.

This was my experience with asterinas. Keep in mind that not everyone has this kind of issue. Some of my comments are not proven scientific fact but just my assumption/opinions. That being we go.
Soon after setting up my 10 gallon I noticed a few asterinas and was told not to worry about them. "They are just harmless grazers" was the general consensus. As the months passed, I too was telling people who asked about them that they are harmless and leave them alone. After about a year there were probably 100 or so in my tank and still nothing bad happened from having them. They were little white ones, some big ones might have been 1/4" wide. They NEVER harmed anything. They did favor a big zoa covered rock and would sit on a polyp for a day or so and when they moved on, the polyp would open back up like nothing ever happened. I had no problem with that. No foul right? As the next year went on, they multiplied into several 100's. Some of them started growing larger than the rest and turning from the bleached white that they were into a tan/brown and grew to about the size of a dime. Here is a pic of a larger one.



As more months passed, I still had no issues. Just figured they were a good part of the CUC and ignored them. It wasn't long after that when I noticed my Orange Bam Bams (zoas) were vanishing almost overnight. There were 17 polyps when I got them so it was easy to keep track of. I checked in there at like 2 AM one night and saw a big star (the one in the photo) sitting on one of the polyps. I reached in with the handle of my glass scraper and lifted the star off the polyp and to my amazement the polyp was GONE! Just a little bit of the stalk and the mat remained. I left the star alone and when I got up in the morning I went to check on the zoas and the star was in the same spot so I flipped it over and EVERYTHING was gone! Just bare rock where a polyp was the day before. Thats when I took that star out. Over the next few days, I noticed more Bam Bams vanished. That got the wheels turning! I might have a problem here. I checked more often in the middle of the night and found lots of the big asterinas all over the zoas. They were vanishing really fast. Thats when I decided to get a harlequin shrimp to "thin out the herd". My LFS said they would add one to their next order and I could get it without having to pay shipping. So I figured "Why not". A week later when they got the shipment, there was no harley in there and I would have to wait 2 more weeks. Not wanting to lose more zoas, I started doing manual removal of the stars but they seemed to show up as fast as I was pulling them out. There were about 20-25 of the larger stars and in about a 3 week period I lost about 100 polyps! Thats when I saw one on a palau green tree base. I pulled it off the tree and there was a trench cut into it that went about 1/3 of the way around it. NOT HAPPY! My nepthea's were pinching off frags like crazy and they were attaching everywhere and on the side glass were 7 trees growing off the glass. I saw a large star on the base of one of those and left it alone to see what would happen. Sure 1 day it cut the frag off the glass and moved on to the next tree on the glass. The trees would lay on the sand and re-attach to the glass and the cycle would start over again. Here is a pic of a star chewing a tree off the glass


You can see in that pic a tree that was cut off the day before laying on the sand. Then my harley showed up YEAH! Emily (my little girl) named him Spots lol. It took a couple months for him to clean out the stars (probably 300+) and was the coolest tankmate EVER! Then he ended up in one of my maxi mini's...biggest tankmate loss ever! Here is a video of me playing "keep away" with Spots. I loved watching him wave his claws over a star as if he's saying "you are getting sleepy"


Were the larger ones that did all the damage a different species...quite possible as I'm no star expert. But my own feelings are that they reproduced to the point that their food was running out and instincts kicked in and they went for the next available food source. Which in this case were softies. If the population is kept in check, you may never have any problems. But if you let them get to plague proportions like I did....You may be in for a bad experience. Just my 2 cents....
Wow...what an amazing story. When I first got them, I let them just be, but I when I saw around 100 in my tank, I started picking them out manually and placing them in my fuge. I've heard horror stories of them doing exactly what you've described. I'm glad to hear you've got them under control and sorry to hear about your shrimp.