Thank you all so much. At last I can live with the look. And more importantly, my fish are healthy!
Thank you. I have had a few warnings about this cave. My flow is much higher than most tanks. I tried to put an airstone in it at first. I didn't think about drilling it. That's a great idea. It kept rising up as it filled with air. I have the back of it against the glass, and there is a catfish living in it. I really do not think I will have issue with a GF trying to get in it. Charlie is way too big. Sumo keeps to the left side mostly. The only one I would worry about would be Moby. He got in the pretty line, but never made it to the smarts line. He has gotten himself stuck in the shell already a few times. The last time I almost thought I might lose him. His throat was scarlet red,then pink for a few hours, and he tore up his fins and tail. He just got out of qt once again just to be safe, with triple sulfa.I have remedied this with a piece of poret foam so he cannot get back in.
Now what I have been doing is as I do a water change, everything gets moved around and turned over. When I did this last one I turned over the cave and stuck my siphon hose up into it. So I am definitely going to keep an eye on it. I can remove it if necessary. Thanks again.