I'd suggest that you read the book of Genesis. It will tell you how everything was created.
The same way apes evolved into humans, through mutation. Also, the same way new viruses and other forms of life are coming into existence today.
I found a program on Discovery explaining the difference between ray-fin fish and lobe-fin fish to be very educational. Lobe-fin fish are our earliest ancestors with the same basic skeleton as humans having distinct finger bones and limbs. Ray-fin fish have the same limb that current fish have such as catfish or goldfish. They remained on that evolutionary tree where we humans branched from lobe-fin fish.
How to Fish was created in 1942.
One Fish Two Fish Red Fish Blue Fish was created in 1999.
Red Fish was created in 2003.
Swedish Fish was created in 1958.
The Diamond in the Fish was created in 1996.
El-Fish was created in 1993.
A Fish in the Water was created in 1993.
Comber - fish - was created in 1758.
Fish's Head was created in 1989.
An Emotional Fish was created in 1988.
Fish Warrior was created in 2011.
Law of the Fish was created in 1987.