How to glue aquascape together?

So I have 5 or 6 peices of live rock in my tank that keep settling and changing the look inside the tank. I want to try and glue all of them together to make one big rock. There's currently fish in the tank which makes the project maybe a little more complicated and I don't want to leave the rock out of the water and get a bunch of die off.

So how do I stick all the rocks together? I tried using the two part epoxy putty but it didn't work for me. Maybe I wasn't patient enough or it didn't like being stuck on wet rocks, although it was designed for aquariums.

So how do I go about doing this without killing my fish?

 

I like epoxy putty, personally. Just knead it and stick it where you want it, it's pretty easy and cures underwater. Just use small amounts at a time and cement everything over the course of a week or two. It may cause your skimmer to go nuts for a bit, as well.

IO makes some (green stuff) that works quite well and is, obviously, designed for aquarium use - you can find it at just about any LFS. Loctite also makes some (blue stuff) that is aquarium safe and can be found pretty much anywhere you can find superglue. I have used both in the past with great success.

 

Two other options....

Taking the rock out for a while won't hurt it. Everything stays moist for probably hours, but you'd only need maybe 30 minutes.

1. drill holes and insert acrylic rods to build support (or plastic clothes hanger pieces) . I dont know if the rock could crack from drilling.

2. If the rock is holey enough, you can use zip ties to secure them togather. Either is more intensive, but will hold better than putty. I don't find that putty adheres well underwater to rocks covered with algae and ?.

 

There's a product called "Mr. Sticky's" that is a true two-part aquarium epoxy (similar to 5 minute epoxy) that will cure underwater. You can use that, as well as drilling the rock and using rods. On our last build, I FINALLY had to break down and put one rod into a structure (a pillar with an overhang). Be sure to use a masonry bit...it makes the job a lot easier, and will be less likely to crack the rock.

That being said, IME, unless you're going for a certain type of structure (overhang, pillar, etc), LR can normally be stacked to where it's super stable. It simply takes practice and fitting each piece into the right spot in the right orientation.

Either way, you don't want your rock squashing your fish...