Eldiablo beautiful tank, I had the same decoration (large rock cave from pet smart) and after about a month when I was cleaning I happened to decide to remove the decoration. I happened to catch a whiff of the water that was spilling out of the decoration to empty it for storage and it was PUTRID. I would find a way to either seal off the decoration so no water can get in like sand and silicone, as the water can get stagnant and can become a cesspool of bacteria, also my silly mollies were constantly scratching their eyes on the "bushes". This decoration is one of the biggest reasons why I am moving all my tanks from hollow plastic decor to nice natural driftwood though slowly as it does lower ph. That was just my thought take it as you will but overall I gotta say you have a gorgeous tank and one happy betta.