DEAD CICHLIDS

Hi.
I have a 200 litre mbuna community tank but I am having some difficulties. I have lost two beautiful fish in the 2 weeks. The symptoms are as follows. The first fish died about 2 weeks ago. One minute he was healthy. The next he started eating less and less untill he stopped completely. He then died after about a week. I have lost another today with the exact same symptoms. They did not have bloat and did not lose any noticable weight. The water parameters are fine. 27c nitrite 0, ammonia 0, ph 7.6 nitrate 30ppm before weekly water change 10ppm after. There are 12 fish altogether. Tank is filtered with a fluval 205 external and 2 internal filters. There was no sign of physical ailments or injuries. Another now seems to be coming down with the symptoms to. So it looks like it is contagious. Please help. :cry:

just read one of your previous post,looks like you dont have your nitrates under control mate.
better filtration and more waterchanges should solve your problems.
i keep africans as well and they are very hardy fish but a WC once a week is a must,30-40%

For africans, the nitrate level seems ok. What kind of fish do you have in the tank and what kind of fish are dying? If your water quality is ok, the biggest suspect is aggression related. How are your fish getting along?

I do water changes at ;east once a week. I have the equivelent of 600litres of filtration. I have spoken to a leading malawi specialist who thinks it may be overfeeding. Any idea about that.

over feeding results in massive nh3, and no2 spikes, if your not detcting them, then its proably not over feeding.