I found this rock around a man-made lake in my neighborhood. I'm not quite sure what kind it is. My mom thought it was limestone, but I but vinegar on it and it didn't fizzle. I then showed it to my dad and he thought it was some kind of compressed coral rock(?). It does have several fossils and small holes in it.
Does anyone know what this rock is and is it ok for me to use it in my aquarium? I was going to to put some java ferns and maybe other plants on it to grow.
I would obviously clean it before I put it in, but I was just wondering if it was safe to put in.
