And back to the other stuff. I was in the middle of typing before when my husband got home so I had to leave it and go and cook dinner.
The pics of the white on those tetras looks normal. There is variation in colour in fish the same as with humans. As long as your fish's white fin tips look like those there is nothing to worry about.
The white spots - if it looks like the fish have had salt shaken over them it's whitespot. Bacterial infections look like greyish white patches. Fungus often has white strings coming out of white patches.
I have had a pair of apistos and a pair of bolivians in my tank at the same time, but your bolivians sound a bit more territorial than mine were.
Cockatoo apistos - mature males are easy as they have very long rays at the front of the fin on their backs. Females are a bit trickier because this type of apisto has males that pretend to be females to avoid being attacked by the dominant male (called sleeper males). I kept what I thought was 1m 2f from the eggs that hatched last year. Two of them went bright yellow when they were excited (when I fed them
) which is typical female but one turned out to be a male - he suddenly grew the long fin rays and changed colour.
The other common apistos are agassizis. They are easier to tell the sexes except for the fire red colour. Again the males have long rays in the fin on the back though not as big as cockatoo males. And yellow bodied ones should be females. Agassizis don't have the reputation for sleeper males.
Yes, those pics do look like what you label them as. The first one has what looks like a male's breeding tube. The second one is a bit more difficult to say but I think I can see a female breeding tube. The third oned definitely has a female breeding tube. I can't see a breeding tube on the last one but its fins look male.
Do your rams have a stone or something flat to lay their eggs on? Mine always chose a flat rock.