Baby mollies have a fairly large yolk sack and tend to sink to the bottom of a tank for the first day or two. Once this yolk sack is absorbed they swim around much better.
The picture looks like it could be in a basement. Two or three months in a basement without water in the tank could have caused leaks. Check the tank really well. Fill it with water if you can, before you decide to buy. Good Luck!
I think 2 angels in your tank would be maximum with the fish you already have. Angels grow pretty quickly and they do like to have swimming room. Here are some sites that might help you to know more about angels.
http://fins.actwin.com/species/angelfish.html...
Two weeks ago when you set up your community tank you changed the bio balance in the tank. You have 35 fish in the tank now. You are probably going through a mini cycle. Frequent water changes are needed until the balance returns. Continue testing the water frequently.
If its a new tank take pictures and take the pictures to the supplier of the tank. They should give you an answer to your question based on the photos.
Usually as the time of birth approaches the bulge in the mother moves toward her rear. If you look really close you can sometimes distinguish the baby fish when they are still in the mother.
With the numbers of fish in the guilty tanks I would make sure to do PWC's at least once a week. After a fish dies do you then replace it, or are the numbers in your sig the maximum numbers of fish for each tank?
A 36g tank with the number of fish you have is very full. You may be at the point of what your system can safely hold. If PWC's and reduced feeding do not solve the problem I would say your tank is overpopulated. and that is what is causing the lowered PH level. If you want to check further...
Guppys are food until they won't fit in the other fishes mouth. If you want to eliminate guppy fry just feed your fish less. Guppy parents will eat their own fry if they are hungry. If you are only interested in the bright colors don't have any females in the tank and that will solve the problem...
Without knowing your tank size and the number of fish currently in it the logical guess would be nitrite poisoning. Did any of your old fish die or are they acting funny?
Congratulations. Let the cycling begin! I hope you are going to cycle the tank completely before introducing the pair of breeding Kribensis. Something to keep in mind is, what will you do with all the Kribensis fry. Your tank will be overpopulated very quickly
It sounds like you have high calcium. mineral deposits in your water line. You may have to do more frequent water changes, especially if you have a small tank. Platies and guppies should be fine with frequent water changes.