The base rocks went in then the sand folowed by the stacks of rocks,
i was thinking of silconing them but didnt no if it would make any difference,
the photo is a lil bit despetive as the bubbles are to one side and are towards the back, but i know what you mean that it woulndt happen in the wild, (but these fish aren't in the wild so meh)
i have got some silcon but dont no if it can be used under water (will it work if the rocks are submerged?)
it is the JBL AquaSil Silicon (colour white)