One option is to talk to the parents of these students, and see what management strategies they use at home for these students. If possible, periodically attending the specials period yourself to observe is an option. Also, you could invite the parents to observe this time period as well. A conversation with the other teacher may be helpful.

A teacher cannot stop a fight from happening, if students are mad and especially being EBD, students at this level do not know how to control their anger, best thing as a teacher is to make the classroom a safe zone, have weekly updates or check ins to make sure students are okay in class. I personally dealt with EBD students who are okay with "slipping the tea" or laying out the drama and once they can trust you, they will continue to check in with you, the teacher, if any threats seems to occur.

Reinforce positive hallway behavior by reminding them every single day what the hallway producers are also reward specific individuals for not fighting. When in the hallway you can occupy their minds by reviewing learning concepts such as spelling words and math problems. Instead of answering out loud have them use hand singles when giving answers. You will not be able to control them during specials because you are not there. Inform them of your special behavior expectations in-front of the special's teacher and pop into the room every so often to let them know you are always watching and expecting them to do well even when you are not around. Reward them as a whole class for their good behavior during specials.

Give your students incentives, if they can behave for you they are capable of behaving for another teacher. Reinforce/ remind your expectations before they attend specials, and maybe implement lunch pal where they can eat with you or some type of reward and you can also just pop up on them while they are in specials and say I like how Johnny is behaving etc.

These students seem to have no consequences attached to their behavior. I would address this first. When in the halls or moving to their next class, supervising their movement might be necessary. Another option would be for the release of those students with a staggered timing so that contact between them is less likely.

I would respond calmly but firmly to an aggressive students and let them know the consequences for their bad behavior.

Try having a conversation with the other teacher. Voice your problems and concerns you are having with the fighting and ask what she is having problems with as well. You guys can work together and come up with a plan to stop the fighting.