My question Is about the part that says that the moon shall ne turned into blood. I have heard that, this prophecy happened not long ago. Is that true? Has the prophet anounced that?

JOEL - No announcement of any such thing happening as far as I know, nor does anyone know the exact time or exactly how this prophecy will be fulfilled.
Among the many signs revealed in the heavens signifying the coming of the Lord are the following:

1. God shows great signs and wonders in the skies.
2. The sun is darkened and the moon becomes "as blood."
3. The absence of the rainbow is a sign that the end is near.
4. The sign of the Son of Man appears in the sky shortly before Christ's second coming.

Some of the other scriptures and quotations from prophets mentioning the moon turning to blood include:

"The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the Lord come." (Joel 2:28-32)

"and the moon shall be bathed in blood". (D&C 88:87)

Isaiah declared "the moon shall not cause her light to shine" (Isa. 13:10).

Joseph Smith said:
"There will be wars and rumors of wars, signs in the heavens above and on the earth beneath, the sun turned into darkness and the moon to blood, earthquakes in divers places, the seas heaving beyond their bounds;" (TPJS p. 286)

There have been many theories and opinions as to what will cause the moon to appear as blood to those who are still around to see it. The moon probably will not become actual blood but becomes "as blood," meaning that it will look red to the inhabitants of the earth.
This change in the appearance of the moon may be the result of the great earthquake spoken of in Rev. 6:12, which would send a great amount of dust and debris into the atmosphere. Such airborne particles could make the moon appear red "as blood."
It is also possible that amid the fires and burnings that shall ravage the earth or because of volcanic ash or nuclear dust from a war, the moon, viewed through the smoke and polluted atmospheric conditions, might appear as red as blood.
It is conceivable that this event could occur when the earth is "rolled back" into its paradisiacal planetary orbit where its light is received from the presence of God rather than the direct solar rays of the sun or reflected rays of the moon (TPJS, 181; JD 17:143).
It could refer to man walking on the surface of the moon which of course already happened in 1969. Or it could refer to a lunar eclipse which makes the moon look red in the shadow of the earth.

Though we may not know the actual cause in the change of the appearance of the moon, as well as any symbolism the Lord intended with this imagery, we can have confidence that this sign will somehow be given and that all the world will see it and fear.