Angelfish behavior

Question
I have a small aquarium and I'm novice in keeping fish!
For start, I bought 2 guppies, a catfish and an angelfish. Also I have 2 shrimps.
The problem is that, my angelfish becomes quite aggressive and  attacks to any fish. Others are used to hide themselves and they are afraid of this angelfish.
However, in first days, the angelfish wasn't as aggressive as now. I saw lots of angelfishes in aquarium living with other kinds of fish in peace. What should I do to prevent attacking? Should I add another angelfish to my aquarium?

Answer
Hi Mahdi,
 Adding another angelfish will make the problem worse, not better.  Angelfish can be quite territorial.  You need to add "structure" to the tank (wood, rock, plants, etc) to break up the space.  That way, the angelfish can claim one chunk of the space as his territory and the other fish can live in the rest of the tank in more peace.  If the space is not broken up, the angelfish will naturally try to claim the whole thing, which is why he attacks the other fish.

-- Ron
  rcoleman@cichlidresearch.com
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