What is it? Harmful/harmless?

[MRB]

The starfish I think are fine, but what are these clear slugy looking things? Thanks!

 

[MRB]

 

[TriggerFinger]

First pic looks like a starfish. The rest look like stomatella snails. All good clean up crew. I also see a brittle star arm with the other starfish

 

[Retro Reefer]

You probably don’t want those little star fish in your tank they will most likely eat any Zoa’s you put in system.

 

[Lovemyreef2015]

First picture is a asterina starfish. Some are good some are bad. I would remove just in case. Would need a better picture for the others to correctly identify

 

[DSC reef]

The hitchiker besides the asterina look like a flatworm. I would not release them into the tank, any of them IMO. Better pics can help with a positive ID.

 

[Duffer]

Where there is on starfish there are many more...need to control them or they get out of hand

 

[lapin]

The asterina stars like some other critters.. bristle worms..brittle stars...,ect are usually not a problem. When they become a problem its is usually because you are over feeding your tank.
I will second that on the slug looking thing as possible flat worm. I would get rid of that if it is.

 

[André Brasil]

That's some mix you've got there xD

 

[Kirschy17]

Id say flatworm aswell. For the stars i wouldnt bother removing them.

 

[Sashaka]

look like a flatworm

I think DSC reef is right. The pic is not clear enough to ID but I would not put them in my tank. Best to remove coral from plug, dip coral, and super glue coral to a dry, clean plug before putting in your tank. Even better, quarantine coral after dipping for a month before putting in your tank.

BTW, stomatella snails have a hard half shell shaped like a fingernail, so they're easy to id.

 

[Lovemyreef2015]

Make sure to post pictures when you can so we can ID those for you

 

[Kirschy17]

When it comes to flatworms, theres like 3-4 species that eat coral that you wanna keep out of your tank by any means. The thing id those are usually pretty easy to id. Besides those theres many other kinds that dont usually cause trouble. Like others mentioned you want to make it a routine to dip and or quarantine new corals to rid them of pests. Keep in mund that if theres 1 critter you can see on a frag theres propably 50 more you cant see.

I use coral rx.