more background--
Last week I had to remove almost every rock out of the tank to pull two females holding fry (yellow labs). I vacuumed with the water change, (as with every water change once a week), but was able to do a great job while I had most of the decor out. No dead fish. It seems that in a day or two the water started to whiten up, almost like a new tank syndrome cycling cloudiness. And it did quickly. By day four, I knew something was wrong. The thread basically starts at that point.
There are lots of hiding places in my tank. (see pictures) I do homeschooling with my children at a table in front of that tank, I look at the tank all the time and stare at the fish

, and take note of how they are doing. However, the yellow labs are the only fish that I have multiples of in that tank. With eight fairly identical looking fish, with the females often hiding, I must admit I do not always attempt to count those. Even at feeding time when all the fish are out from all the nooks and caves, it is such a frenzy, that it is not so easy to say: "oh yeah there is all eight labs". If it was any other fish I would have noticed. That may sound weird, odd, lazy or mean.
I am not offended by any of your inputs or suggestions.
I thank you all for caring enough to respond. I do not believe I am being over defensive, (
even though I am sounding like a lunatic right now
) I maybe did not include enough back ground information. I was trying to keep the post to a readable length. I am often accused of giving too much information.

BTW: I did another water change today, thanks for the suggestions. I think the stinky water was from the dead fish. It seems to be better today.
Here is the run down of fish in this tank (1 of 9 tanks. about 155 fish. in total)
7 (4M,3F) yellow lab
1M Blue ahli
1M kenyii
2M red top kapuna
1M Red zebra
1M Zebra
1M Yellow princess mlotto
1M hybrid peacock
1M Rock krib
1 ? Jeweled
1M Frontosa
1M Acei
2M Sunshine peacock (1 LG, 1 SM.)
1M Red peacock
1M Aulonocara Jacobfriebergi peacock
1M Labeotropheus fuelleborni
1M ice blue zebra
2? OB peacocks
1M Geo japari (S. American cichlid)
4 giant danios
2 sailfin plecos
1? yo-yo loach
