Get a voltage with trhee numbers in the right side of the point.

I want to read a voltage betwen 0 and 5 but the serial monitor only shows two decimals, ex. 3.55, and i want to see trhee decimals, like 3.554, Can I do it?

int VALORPUENTE=analogRead(A0);
float voltimetro=VALORPUENTE*(5.0/1023.0);
int ficha=0;
int LABEL=1;

void setup() {
Serial.begin(9600);
Serial.println("CLEARDATA");
Serial.println("LABEL,HORA,VALOR PUENTE,ficha");
}
void loop(){
int VALORPUENTE=analogRead(A0);
float voltimetro=VALORPUENTE*(5.0/1023.0);
ficha++;

Serial.print("DATA,TIME,");
Serial.print(voltimetro);
Serial.print(",");
Serial.print(ficha);
Serial.println("ROW,SET,2");
delay(1500);
}

Serial.print(floatingPointNumber, 3);

will print to 3 decimal places. See the Serial.print reference.
The print function default to 2 places, as you have seen.