How to prevent rock from falling

[M3AN ONE]

I recently aquascaped my tank with about 200-300 lbs of live rock. It has many caves and am woried that if I get a golden moray eel for my reef tank it will cause all the rocks to collapse thereby killing everything.

I put eggcrate under the sand for added support but did not leave the rocks buried under the sand because I ended up with 3 inches of sand and made everything apear much shorter rather than taller.

 

[M3AN ONE]

Also could a fish be able to knock over a 5lb rock or is that unlikley to happen

 

[Neno reefs]

Yes it could happen, there are stories of people that had there rock fall, completely broke the tank and everything died. And yes if the rock is not sturdy even a fish could knock it over. You said you have it on top of the sand, that wasn't a good idea because your sand will move over time and that could tuble the rocks. I used zip-ties to help hold my rock together. Some people also use putty and pvc rods yo hold together the rock. The other main thing you need it a sturdy base, this can be done by useing base rock. I always give a rock a push with my hand to make sure they are sturdy,

 

[M3AN ONE]

I used putty and I started the rock against the back wall stacked it to the top reinforced the bottom and built from there but If a fish can move a 5-15 lb rock im sure everything would come down. at least in a section.