What are these things?

[jambi0n]

Ok,
So I was looking in my tank just right now, and I saw this bug. Can't seem to find out what it is. Also there are smaller bugs next to the big bug. Anyone know what they are and if they will cause any harm to fish.

 

[jdragunas]

The bug looks like a nudibranch. Probably a hitchiker. Not sure exactly what kind of nudibranch, though. I could be wrong, so don't hold me to it.
The little white bugs i've heard about, but i'm not sure what they're called. I think they're harmless to your tank, unless you don't like the look of them, then you can remove them.
This is just what i believe, i could be wrong, so wait until you get more opinions.
Jenn

 

[bigarn]

I agree ... the large critter is a nudibranch. The small critters are probably copepods which are good to have.

 

[jambi0n]

so the big guy is a nudibranch? are they harmful to a reef tanks?

 

[jdragunas]

i don't believe so, but they're difficult to keep. Try to get a better picture of it, maybe the back of it. Then you can tell what kind it is. Some nudibranches are photosynthetic, and need great lighting. Some aren't. They feed on algaes. Not sure about yours, but i know they have specific diets. I was looking into getting a lettuce nudibranch, but found they only eat one specific kind of hair algae, and most die after a few months. I'd research nudibranches and find out what kind yours looks like, then find it's care requirements. Good luck!!!
Jenn

 

[bigarn]

The nudi in your picture looks like it may be a coral muncher ... I'd keep an eye on it or remove it completely.

 

[jambi0n]

right on... i'll try to find it again... it got knocked off when i was mag sweeping my glass.

 

[salty cheese]

One of the coral eating Nudibranches.

 

[jambi0n]

Saltycheese... that's exactly what it looked like, but it didn't have the green legs yet. Is it that big or were you able to get really close for that pix? Cuz that's huge!