Need Help ID Please. Thank you

[Myka]

Like Tony says, sargassum isn't the end of the world...it won't "take over" or anything. You can keep it for now, and see if you like it.

Hydroids can be a real pain in the butt...they are difficult to eradicate. I have a couple small colonies in my tank, and as long as I tweeze them every once in awhile they don't spread too much.