Cichlids need help.

Question
Dear Ron,

I have a tank of about 30 Gallons and it houses about 5 pairs of African Malawi cichlids.Recently 2 of the electric yellows died  and one of them had has red scales around its posterior towards the tail.I put it in a quarantine tank(bucket filled with a  pinch of salt),but it did not survive.It was showing signs of aloofness earlier but I did not bother much.
Few months back,I had few cichlids dying because of this red scale disease(thats when I upgraded my tank and got a big one).I do water changes in my small tank  (75% once in a month) and weekly,I clean the filter.
Also this time when I made 75% change on the advice of a friend ,I have this feeling that I might have added more amount on first aid medicine.Could that be a  cause of death?
This week,I did a 25% of water change and added 2 drops of medicine just that it takes care of the parasite/worms.Now I see few of the fishes are there at the surface breathing but they seem to be very normal.I am worried now.Could you suggest what I could do to save them? Change 25% of water again without any medicine?
Also being in India,we don't have a Wallmart where I could get the nitrate/ammonia checker to check water chemistry.
The remaining fishes look allright as of now.But from my experience,I think this disease will migrate onto other fishes as well.

Answer
Hi Ashwin,
  The red scales are most likely caused by attacks from another fish, not disease.  
You should be changing less water more frequently, i.e., it would be much better to change 25% once a week, than 75% once a month.  You cannot do water changes too frequently, i.e., you could do a 25% water change every day and that would be perfectly fine (though quite a bit of work).

 You don't really need to check the chemistry. If you do regular weekly partial water changes, everything should be fine.  I actually NEVER check my water chemistry and I maintain 140 tanks.

-- Ron
  rcoleman@cichlidresearch.com
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