My blue circhlid seems ill

Question
Hello,

I have a blue circhlid (1-1/2 years old). For months now he has been less energetic as he used to. His fins appear slightly shredded and his mouth looks white. He lives together with a yellow circhlid, freshwater shark as well as an angelfish. None of the other fishes have ever been ill. I have treated the water with both salt and methylene blue. The methylene blue seems to help slightly but i find that i have to treat the water with this every week in order to get the small results that i'm getting. I clean the tank once a month. The tank holds approximately 30 gallons of water. What's wrong with my fish? Please help!!

Answer
Hi Salma,
  You really should be cleaning your tank more often than that.  I highly recommend changing 25% of the water once a week, every week.

  I suspect your cichlid is being picked on by the other fish, most likely the yellow cichlid. One way to reduce this is to make sure that you have LOTS of structure (rock, plants, etc) in the tank to help break up the space and to provide hiding places for the weaker fish.  

-- Ron C.
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>