Its not a good idea to use silicone inside the fish tank because the chemicals the silicone contains can get mixed to water where it would effect the fish.
Its not a good idea to use silicone inside the fish tank because the chemicals the silicone contains can get mixed to water where it would effect the fish.
Please don't make random guesses on this site or respond to a questions that you don't know the answer to.
The seals of your aquarium are made of silicone, as long as you use 100% silicone (ie: GE Silicone 1) and allow adequate dry time (a day or two) then you are safe using it in your aquarium.
As far as using it to hold down plants, I'm not sure, as I've never heard of anyone doing that. Most commonly, people tie their plants to rocks or wood with fishing line.
Superglue for attaching Anubias and ferns to hardscape, and yes it's safe (I've done it multiple times and reefers do it in aquarium with thousand dollar+ stock in it).
I've fragged coral for years using superglue. I wouldn't use it for plants, but that's just cuz it's so easy to tie it to something with fishing line. If you're going to go the superglue route, it's needs to be the gel type. The regular superglue won't work and coral/plants will be affected. The gel type will specifically say "gel" on the front of the tube. No guesswork. If it doesn't say "gel" in big bold letters, don't even pick it up.