behind the skull you can see the goby's tail i have pics and vids on my photobucket there. on the left was the original gravel green and black it looked really nice when i had my betta's and dwarf gourami in it but the goby needed sand so i went out and bought some argonite cleaned out about 3/4's of the gravel and put the sand in.
i got the skull and the goby at the same time and he loved that cave it was all nice and cozy for him. he out grew it and it got moved to daughters crawdad who loved it and now it's in other daughters betta tank. i filed down the edges so they are all nice and smooth for the fish no torn fins or irratated skin.