something on coral and bugs

okay so its midnight over here but i was about to go to bed when i thought i heard something go off in my tank. i havent really payed attention to my tank for a couple weeks. so i noticed that one of my corals fell down. when i went to move it those white looking bugs all crawled away from the rock. when i look closer on the sand there are like hundreds of these bugs. also on my coral there is this black kind of purple looking thing stuck to it and i know i did not buy is with that. i only bought it a week ago so its weird how big that thing is. i have pictures of it.
soo what is that thing growing on my corals rock and what will eat the bugs that wouldnt be aggressive to my fish?
thank you

 

the bugs are probably harmless copepods and Amphipods - many fish will eat them and they are a good thing to have in a reef tank

the black purple thing is probably a sponge or demi sponge and again is a harmless filter feeder that is a good thing for your tank

Steve

 

yah i know the bugs are harmless but there is so many of them now! haha
how big do you think the will sponge grow and will it destroy my coral if it starts growing more??

 

I doubt the sponge will reach any size that will create a problem, most of these hitch hikker type sponges dont get very large and more often than not die off before they are a problem

Steve

 

Some sponges can be "aggressive" by growing over and smothering your corals so keep an eye on it and remove if necessary.

 

okay well if it grows anymore its going to hit the coral so i think im jst going to remove it thanks