I have seen some DIY caves here and there online and I couldn't resist trying to make one. It was alot of fun and I encourage anyone to do it. I bought a piece of pvc pipe (3 way) from Home Depot and cut off about 1/4 off the bottom for more of a cave look. Using Aquarium Sealant (from PetSmart), I glued dried gravel (from my tank) and a few plants onto the pipe. It cured for over 48 hrs before I introduced it into the aquarium and my weather loach loves it! A few of my bala sharks have gone through it and one of my black skirt tetras hid in it when I was trying to net him.