hi guys i was looking around on the internet at fish tanks and saw this one guy that had an underground PVC Pipe tunnel system in his saltwater aquarium for his eels. i was thinking about doing this for my senegals when they get around 5inch and i put them in my 55. just wondering if they would even utilize it and what would be a good diameter for the pipes. i was thinking about also getting a Gymnothorax Polyuranodon, but it seems they are very scarce in the trade. any advice would be great, thanks!