Some of my friends who are evolutionists & atheists told me that all humans have ancestors who were fish going back hundreds of millions of years. Why would they say such a ridiculous thing?

 Evolutionary theory, supported by a wealth of scientific evidence, suggests that all life on Earth shares a common ancestry. Over millions of years, species have undergone gradual changes through processes like natural selection, genetic mutation, and adaptation to their environments. This perspective aligns with the principle of common descent, asserting that diverse forms of life, including humans, can be traced back to a common origin. Fossil records, comparative anatomy, and genetic studies collectively contribute to the robust body of evidence supporting this evolutionary framework.

When your friends mention humans having fish ancestors, they are likely emphasizing a specific aspect of evolutionary history. According to this perspective, early vertebrates, including fish, represent a common ancestral lineage for various vertebrate species, including mammals like humans. It's not a literal claim that humans were once fish, but rather an acknowledgment of shared evolutionary roots that extend back millions of years. The gradual changes over time have led to the incredible diversity of life we observe today.

It's essential to note that the scientific community widely accepts evolution as a cornerstone of biology. This understanding doesn't negate religious or philosophical beliefs but provides a scientific framework to explain the biodiversity observed on Earth. Many individuals, including religious scientists, find harmony between their faith and the acceptance of evolutionary principles. Recognizing the scientific consensus on evolution doesn't necessarily conflict with personal beliefs, as science and spirituality often address different aspects of human experience.