the abs does fine in water, no discoloration, and no cichlids tried to eat it,lol, butmy oscar does pick one up and move it, burning it makes a mess, sand also works good instead of gravel, i used ge1 silicone to glue them together, i've also never had a problem with hot glue in a tank before, for texture, why not just cut a piece of abs into small pieces and silicone it on in different places before adding the gravel. also if you rough up the pvc/abs with sandpaper before adding silicone it will last much longer.