I've tried many ways to secure rock work , never had much success , Than I discovered the simple stack and lock it's just fitting rocks to let the rock next to it lock it in place ,
it takes a few times to get the correct pattern but once yo get it it works like it should ,
think of the rocks in a natural reef no one spent time gluing every rock in place nature placed and locked them , macro's pay a big roll for holding rocks together as they vine or just adhere to the rocks corals also help the cause especially encrusting corals and also most of the softies , my method is basically a carbon copy of of the reefs it don't totally work until things grow out but I never had any moving or rocking rocks .
one tank I had several of the fish loved shifting rocks around . I thought a few times I was going to come home to a broken tank but I got lucky the stack and lock works I do it in all my tanks now never have seen any problems since , now with coral frags I glue them to dry rubble rock I think it looks better than plugs and than find a crevice to lock it in , over time the frags start growing out that also help lock things in place ,
there is only 3 fish I know of that love to move rocks . Clowns , Damsels ,and of coarse triggers , I'm sure there are others but I still haven't encountered them .
Fish are like lifesavers
They come in different colors