Loaches Online Forum

I'd like to glue some stones together to make some nice arches and caves for my fish, but i'm unsure which glues are fish safe. I'm only talking about cobbles not large stones. I'd thought about CA but i'm not sure if it would be too brittle?

years ago I sent a mail to Pattex/Henkel asking about their clear hot melt sticks and got the reply from Pattex, that they were absolutely save under water, once cured completely. The only risk they pointed out, that reptiles could bite off little pieces and get a problem with breathing (mechanical issue) but NO poisoning. It was recommeneded to rinse and leave the cured glue for a while in some water before putting into a fish tank.

I cut (common) slots into Stones (flex, angle grinder) and fill the cuts with the melt glue to obtain form-locked joints. I was not sure whether the bonding in itself would be sufficient.

I used aquarium silicone for small cobbles (size of my palm), and it worked pretty well.

I know that aquarium silicone would be good. You could also use the plain hot glue sticks. I hear they work pretty well. Just ask around or look up a particular brand first.

GEL type of super glue. It is safe even for gluing live plants, and is aquarium safe once it sets up, with takes just seconds. Plants don't even have a chance to dry out.

I have had bad luck with silicone. There is an under water epoxy that I see at the fish stores. I do not know how strong it is, but I would give that a try. It looks like a stick of clay in the package.

I would thrust only aquarium silicone...

GE Silicon II for windows and doors is OK. Kitchen and Bath has mold inhibitors that may (or might not) cause problems in an aquarium. But if you only need a very small amount it might be better to get the little tubes (not caulking gun size) of aquarium silicone.