Bullfighting prohibited in Islam
1-11-2016 | IslamWeb
Question:
Is bullfighting or watching it considered a sin?
Answer:
All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Bullfighting is impermissible in Islam because it involves provoking the animal and torturing it for no benefit, merely for the entertainment of the audience. Ibn ‘Umar 
reported that it is disliked to instigate fights between animals. [Al-Adab Al-Mufrad] Scholars underlined that instigating fights between animals is prohibited. Al-Khateeb Ash-Shirbeeni 
wrote, "Instigating fights between animals is prohibited." [Mughni Al-Muhtaaj]
It is known that bullfighting involves more torture to the bulls than the mere instigation of fighting; therefore, it is prohibited for a greater reason.
The Islamic Fiqh Academy, an affiliate of the Muslim World League, during its 10th session held between 24-28 Safar, 1408 AH (17-21 October 1987) in Makkah, decided the following:
"Third: Bullfighting: As regard the bullfighting that is generally held in some of the world countries and which leads to the killing of the bull with the smart use of arms by the trained human being, it is also forbidden in the Islamic Sharee'ah because it leads to the killing of an animal by torturing it and hitting its body with arrows. It also often leads to a situation in which the bull kills its human wrestler. This is a savage practice that is rejected by the Islamic Sharee'ah, as Prophet Muhammad, sallallaahu ‘alayhi wa sallam, was reported, in an authentic hadeeth, to have said, 'A woman was punished in Hellfire because of a cat that she detained and tied until it died. She neither fed it nor let it eat the insects of the earth.' If this detention of a cat causes entry into Hellfire in the Hereafter, then what about those who torture the bull to death with their arms? Fourth: Instigation of animals: Regarding the instigation of fights between animals that is practiced in some countries, such as fighting between camels, rams, cocks, and so on, till these animals injure or kill each other, the Council decides that such a practice is forbidden. May the blessing and peace be on Prophet Muhammad, sallallaahu ‘alayhi wa sallam, his family, companions, and all those who followed his way of guidance."
If we say that bullfighting is prohibited, then it is also prohibited to watch it because watching prohibited acts without changing them implies acceptance and consent to them.
Allaah knows best.