Would it be beneficial?

[mxmbulat]

Greetings,

I have set up on Tuesday a 10G Tank. No cycle yet. A friend of mine who has 2 fish-tanks offered me a bottle of his tank water from a freshwater tank with 3 piranhas. He said that it would help my aquarium to mature quicker. Now I wonder if this water is really beneficial. I have read an opinion that the good bacteria resides more in gravel substrate, walls, plants and filter. So what would you advise - pour the bottle into the tank or into the kitchen sink.

Sorry to be such an ignoramus...

[ZeroSystem]

As you have already read, the bacteria does attach itself to the gravel and filter media ect. So adding the water from your friends tank will not really help, however some of his gravel or filter media might, a little bit.