good or bad bristleworm?

I've never gotten a great shot of some of the bristleworms in my tank. I had heard the majority are good, but it never hurts to check. Especially when the capture was by sheer chance. Of course, I suppose it's also likely it was there because of how much food this acan has been getting thrown at it lately.

 

Your right most likely there because of the presence of food and to clean off the dead tissue of the acans.

 

If you look at the middle top acan, and go just up and left... is that a copepod?

 

Here's a better version

 

Amphipods do the majority of the cleaning up especially on corals with tissue problems. You often find them right after the lights go on eating any left over food stuffs or dying tissue.

This is a good link for zooplankton ID like Copepods and such.
Hitch Hiking Copepods, Isopods and Amphipods

 

Yes. That's an amphipod

Sent from my phone using my two opposable digits

 

2 of them, actually! Better/closer image showed more detail ;-)

Ps: bristleworms are a good part of your cuc and they help the tank imo. There are people that remove them and there are even bristleworms traps for sale at most LFS but they mostly remove them because it gross them out for the most of it.... something it would never happen to me

Sent from my phone using my two opposable digits

 

I know about bristleworms and their role in the CuC... but I also know there are some bad ones. Such as Hermodice. If I have found a bad one, I want to remove it.

 

Looks like a common bristle worm, they're generally considered good, most people remove them when they get big because they are unsightly and at larger sizes, have the potential to harm/kill coral and fish.

 

Those would be the bad ones that do that regardless of size. Common ones do not change into fish/coral eaters just because they're larger!