Fifty-two. That's how many guppy fries I have now and also it's the number of choices I have for making a new guppy breed.
What a perfect intro to an essay. Thanks for letting me read this excellent piece of writing. It really is high quality stuff, good enough to be the intro to a chapter in a published book. Just a little editing is needed:
I'l change the commas a little:
I couldn't understand why people have fish instead of dogs or cats,
as a pet because I cannot pet them, walk with them, or play with them. But my question didn't remain unanswered long, because I figured out the unique characteristic of guppies. I can make my own breed of guppy.
use a hyphen:
scissor-like
Guppies are more than a pet to me because they opened a new door for me: I can do experiments and studies on guppies. --- hahaha excellent!!
I think Rayniv's advice about too many ideas it true about the 2nd para, but I hope you don't change the 1st para too much!! It's great.