hitchhikers: what are they good/evil...?

Hey guys... I've noticed a few more creepy crawly things in the tank:
snail(I think) without a shell...???
little tiny bugs, black, come out a night...???
A centipede looking thing about an inch long and maybe 1/2 centimeter in width...??? All of these seem to come out at night, I've noticed them very early in the morning!
I don't have a decent pic as my digi. cam. wont focus that close on the rock.
Any idea as to what these things are, are they ok for my tank, and what should I do?

 

The "snail without a shell" is the toughest to ID. Its probably a seaslug of some sort, but it could possibly be a cuke or something else. This is probably good, but can't really say for sure. To my knowledge most of them are algae eaters. The "little tiny bugs" are most likely copepods/isopods, which are very good to have, especially if you want mandarins or sand sifting gobies. The "centipede looking thing" is definitely a bristle worm which is a very helpful little scavenger to have.

 

keep in mind most bristle worms are good means that some are bad. my opinion
if in doubt,
take it out

 

After doing more surfing, I found a pic of an identicle specimine: Stomatella... This is definately what it is. Good or bad? What is their purpose?

Thanks for all the helpfull info... I love this site!

 

I agree on the Stomatella.. I thought a snail lost it's shell when I saw one.. I think my shrimp ate all my bristleworms.. I haven't seen one in months.

 

that's what I think. They are good, they eat algae, come out at night.