superglue
 

Can superglue be used in a tank to anchor plastic/silk plants to rocks or would superglue poison the fish?

Not the best choice, use aquarium silicon.

before everyone tells me that silicon might be a better choice,,i have a reason for asking,, again, can superglue be used in a tank with fish?

What's your reason? :)

i do not like the look of the gob of silicon so i want to know if superglue is safe since it will be invisible when used

You could try an epoxy like one of these.
http://www.marinedepot.com/aquarium_...xy.asp?CartId=

ok, lets try again,, is superglue safe in an aquarium?

No.

I have never used it but I know some that have and have never had a problem with it. The arcsenic released is released at the time of the cure or bonding and very small amounts don't seem to have any residual effects. Make sure to rinse the article veru well to remove and dust or aresnic possibly left over and it could work fine. I have even heard of those that use use it to secure coral and living rock unto the formations they want because the silicone is too bulky and won't cure fast enough.

thanks for the answers, i have decided to use it