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I've bred guppies in one tank with the parents before. If you have some java moss then should help the fry hide and feel more safe.
How old's your tank? 5 days only? Fish might have died because the there's not enough beneficial bacteria for the amount of fish you have. You can't rush "cycling" the tank properly. It's common n00b mistake. I made the same when I started. Should probably only have 2-3 fish for a 10 gallon for a few weeks.
If your water is brownish it's from the wood it usually isn't an issue. It will lower pH though.
If it's cloudy, it's likely a bacterial bloom due to the fact you have too many fish and not enough good bacteria.
Tips for Cycling Your New Aquarium - The First Tank Guide - Getting Your Fish Tank Up and Running with Minimal Headaches
PM me if you have any issues or give me a shout if you still have my number.