So i am going to be reworking my 30 gallon fish tank and i got the idea i would make a coconut shell cave and put it in a corner than make a hill over it so just the enterance is exposed any ideas on how to make it or is it even safe. I have never seen anyone make it and if it would work i think it would be great. Also any idea on cleaning it? Also it would be for my vampire shrimp (there would also be the air stone infront of it for the shrimp)