Marine skull coral

This is the final stage pic of my fish tank. For those who are having a hard time with figuring out what the world is those black things are, they are (Halloween) tomb stones (4 in all) with green glass stones across black gravel. In the middle is a skull casting and behind it a fake tree stump. In front of the tomb stones are a fake log and a fake coral reef hill. In the tank is 20 different kinds of fish (mollies, one beta fish and a few random fish, I can’t think of there names at this time but they were cool looking) but most of them are black and gold, goldfish.