Do you know what your guppy died of?
Some fish live an aweful lot longer than others, if you don't want your daughter to experience many fish deaths at a young age then it may be a good idea to go for a longer lived and hardier fish than guppys (which live for 2 years maximum really, although a lot less for a lot of people), as guppys are not the hardiest nor longest lived of fish.
On the other hand though...
I would explain to her that the way guppys reproduce and live is nothing like how we do it in many senses, like how guppys show no parental care towards their young, and although the male guppys death is sad, it is not a problem for his fry, who will carry on his dynasty

. I have some guppys which stretch back from very long lines of pet guppys, its nice breeding them as in a way the offspring can act as living reminders of guppys who passed away many years ago.
Guppys are definately very intelligent little fish, but try not to humanise them too much as they are still essentially fish and have evolved to meet the challenges of life in very different ways to us.
Hm...Death is a major part of life. Hopefully your daughter will get over this experience fine and use it as a learning experience, coping with death is an essential part of life/living, how we cope with such experiences is an important ability

. I hope when the fry are born, it'll take her mind off the loss of the male guppy and she will become occupied with the new life in the tank and enjoy the experience of raising the little fry into young colourful adults

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