Weird Growing Object in Aquarium?

Question

My Dad has a Saltwater fish tank, and there are some large rocks in it. On one of these rocks, there was this little blackish ball shape object imbedded in one of them. I've always wondered what it was. Not long ago it got larger and larger, and now it is about the size of a golf ball. It stopped growing now, but it still looks black, and it feels hard. Does anybody have any idea what this could be?

Answer 1

It isn't uncommon for things to appear on or inside live rock. Unfortunately, "black, ball-shaped the size of a golf ball, and hard" isn't a good enough to description to identify what it might be, and whether or not it poses a danger to the other animals in tank.

Get a picture of it, if you can, and take the picture to an aquarium store. They should be able to figure it out.

Answer 2

eww sounds like the fish tank needs a lil cleaning sense mysterious weird things are growing...hurry befour the lockness monster comes out...

Answer 3

Maybe it's a kind of coral or something, I know some live rock comes with stuff that's ready to grow, like anemones or urchins and those weird colorful salt water plant/animal jiggies (lol I don't know what they're called). I suggest taking it out of the tank and taking it to a salt water fish store, they could probably tell you.