How do you route cables into a tank without leaving a gap?

[Silod]

I hate this problem!! Ive run into it a few times...ironically enough the firebellies are always the ones to escape!! SUCH GOOD CLIMBERS!!!

Yeah, what the heck! They do seem to be climbing a LOT less since I upgraded them to their twenty-gallon and their enthusiasm also seems to be abating as they get larger (they're now about half grown). At first, though, it was as if it were their collective lifelong dream to be tree frogs!