Starfish - Friend or Foe?

[King Detritus]

This guy showed up in my tank. I'm guessing he's a frag hitchhiker. Can you identify him? This is the best photo I can get. The top looks like he has pepper speckles. I will monitor for a better photo opp.

[King Detritus]

Ok he moved. This is the top side. He's at the water line so hard to get all of him.

[mcarroll]

Check out the number of legs.  >5 legs supposedly means Asterina sp. starfish.  Definitely seems true IME.  (The "extra" legs are probably going to be fragged off to make a new starfish soon.  Seeing 2- and 3-legged Asterinas is pretty common.)

 

I've had them for the whole time my system has been running (10+ years), and they've never bothered anything other than algae.  My system has always been fairly balanced though...started with live rock and there were never any big shifts in bio load.

 

"Automatic" cleanup crew (eg Asterinas, Limpets, Bristleworns, etc) will match their population size with the bio load you provide.  Perfect!   (Usually.)

 

If your system or your feeding routine have problems (eg over-feeding, over-stocking, etc), it's possible to create large population spikes of these critters.  Once these problems are resolved, it can lead to mass-starvation conditions.  When critters are starving, behaviors often change – sometimes non-target food organisms become targeted.  When you have LOTS of critters starving (any context), it can be a problem.

 

These are pretty easy problems to avoid though.

 

Avoid big changes, and keep the hobby's motto in mind: Nothing Good Happens Fast In A Reef Tank.  Taking your time can make all the difference.

[King Detritus]

@mcarroll Thanks again for your help. I tried to grab it earlier to put in a cup for a closer look. I dropped it and lost it in the tank. I was kicking myself for losing it hoping it wouldn't be the start to an infestation. Your detailed response puts me at ease. I only have one clown in a 16g nano. I've gotten pretty good at only feeding what he eats. The only exception is I do broadcast feed frozen for the corals a day or two before the water change. I can skip that for a few weeks to see what happens on the starfish front before I feed an infestation!