Sorry your lost some of your fish,
fish are just fickle animals, they're great one minute and the next they're cowering in a corner for no apparent reason. Sometimes they just need some time to re adjust and some times they just don't make it. And often we have no clue why, just so many factors that can change things so fast. And often the ones that don't make it were our favorite fish and it just makes things worst. So again, sorry you lost some of your fish.
On another note, you need to find out what is going on, and eyeballing your fish is not enough to say they are fine, sometimes you're just not going to see what is going on with a fish. Like Discus, one minute they're fine, beautiful colors, swimming gracefully around. And the next they're gasping for air, color flushed and not swimming at all. And most of the time it's the simplest things that make them go down hill. A change in temp, bad water, frozen fish food (high in nitrates) that they're not used too. Some times it's other fish, tail pickers and bullies. So many factors that can just wreck havoc in a tank.
So where to begin, what has happened in your tank lately, other than the mishap with the female guppy. Have you recently changed anything, including your water, is the temp the same? What is the temp and can you raise it say 3 degrees to combat anything that might be going on, sometimes that works. Also, what are you putting in the water, any salt, any fish treatments? And ick doesn't have to be seen to be ick. There's a lot of factors. I kind of agree with one of the replies, the babies seem to be fine but the other fish (guppies) are affected, sounds like a water problem, What about the other fish, any thing, how are they doing? I'm looking at some things right now about Guppies, like you I read a lot about fish and maintaining them. I'll post somethings I've found out that may help you out. In any event, you'll make it and things will return to normal soon.
Be right back