Underwater 'glue'

I want to stick some ABS sheeting onto the back glass of my tank WITHOUT emptying all the water. Is there anything that will stick underwater. Prestik does not work - tried that already. Any suggestions ?

 

praley's putty will work but that is not so cool for plants and fish when uncured AFAIK

Put the ABS on the outside ..

Oh yes silicone might work - but is does not like to stick to ABS ... not sure about the toxic affect while curing

 

Glass is painted black - trying to change exactly that. Why did the tank builder persuade me to PAINT the back glass black in the first place -should have used some vinyl instead - would have made life a lot easier

 

depending what you painted it with might be easier to remove the paint ?

 

Tank is against a wall and I'm trying NOT to have to empty 1000 L of water and all the fish to change the backround.

 

FOUND the right stuff. I went to a florist and got myself a product called OASIS FIX( the imported one). Florists use it to stick plastic things underwater to hold blocks of Oasis - It looks exactly like green Prestik - comes on a 5m roll. Stuck my pieces of ABS onto the back glass panel a week ago when I did a w/c - filled the tank again and covered and it and works perfectly - the panels have not moved at all - tried to pull them off yesterday afternoon during a w/c to test it and the Oasis Fix is certainly doing it's job !!