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I'm thinking your tank was uncycled and that, along with the stress of the ich, killed him. It typically takes much longer than 10 days to cycle a tank. Did you use a piece of filter media from your friend or a bottled bacterial supplement? If not, your tank likely wasn't...
I would give them a week or two to establish the pecking order. If that doesn't work out, I would either remove the aggressor and/or add 1-2 more males to spread out the aggression.
With females you'll soon be overrun with fry unless you have ways to rehome or sell them.
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Unfortunately a 6 gallon just doesn't offer them a lot of space to get away from each other. If you really want to succeed, give them at least a 20g with 5+ females to spread out aggression and a lot of plants and things to break the line of sight.
I think you'd get interesting results, good luck!
As they get older, remove any that start developing a gonopodium. It's easier than removing the females since some males are late-developers and look like females for a while. They can't mate successfully until it's fully developed, although...