What are these?

[ragc]

I posted these in another topic, but it may be so old by now I may not get any eyes on it.

I found a small starfish in my 3 month old tank this morning. I had had these when I set up the tank as hitchikers, but this one developed from what I think are small star-shaped larva I've been wiping of my glass with my mag cleaner. I also have what appear to be snail fry, and also some shrimplike critters... I am attaching photos. If you know what they are please let me know, and also if they are a problem or sign of a problem...I kind'a like them in there....

 

[jessie]

the third one looks like a microstar. i have hundreds of them in my tank. they dont bother anything, inland aquatics sells them in their detrivore kit, and individually for about $2.50. mine multiply like crazy.

 

[mogurnda]

Thing one looks like a hydroid medusa. The medusa stage is not a problem, but polyps can sting adjacent corals. Most of the time, you may not even know the polyps are there, though.

Thing 2 is a small isopod. They can occur in large numbers, and seem to graze on algae on the sides of the tank.

Those are nice photos, by the way.

 

[skippy2]

1) hydroid
2) isopod
3)asternia star
4) ?

 

[ragc]

Those are nice photos, by the way.

Thanks!

Shot with an old Sony FD Mavica 1.2 megapixel camera using the macro focus setting...old technology works if used for good purposes!

I gather then I should not be concerned with knocking the hydroids from the glass...need to clean some of the algea and diatoms...

I had tons of isopods before, and they did graze on the algea (but did not seem to eat much of it). My last manual algal removal must have decimated the population...are they good food for my Damsel?

I also had one other star hitchike in my rock. It died some time ago in a newbie salinity spike...where did this one come from? No new rock has been added since!

The fourth critter appeared this morning for the first time. There were about ten at lights on, but they headed for the sand fast. My nassarius snails spend a good time either fighting or mating (?!). I suspect this comes from that...

Thanks for all the replies!

 

[mogurnda]

The isopods are probably still in the tank, but just grazing off the substrate where you can't see them. The damsel should enjoy snacking on them.