Weird Growths In Tank

[andy.ahad]

Hi all

I've been away for a few days and returned home to find weird looking growths in one of my tanks. I've never come across it before. It's all over the glass substrate and ornaments, and I also had 4 dead fish!! I.ve attached a pic in the hope that someone can ID the problem and give me a solution.

Cheers
Andy

 

[WILDER]

How long has the tank been set up.
How many gallons or litres is the tank.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.

Can you describe the white things in the tank.
Texture, if they move.
Get one of the white things out with a net to take a closer look.