when i was visited a friend's house
I'm sorry, but the original was is actually correct ... :]
2.but back away immediately when i I tapped the glass
Both ways are grammatically correct.
all were interacting like they were a family in the 160 gallon aquarium
Here is my correction: "... were interacting as if they were family in the 160-gallon aquarium'
4. That the same night I returned home with a million millions of questions related toabout (This sounds less awkward) fish but no idea where I could find the answers
There were times when the water would turn dark shades of green, but that didn't stop me from being lazy.
I'm a bit confused here. What are you trying to say? I think think sentence is in the wrong place, or you should add more details earlier leading up to this sentence, like: "When received my first fish tank, the water would ... " Do you understand?
When I hit the peak of my interest in ichthyology, I was starting 7th grade.
Another suggestion:
"By the time I started 7th grade, I was fervently interested in ichthyology"
In fact, I became more excited to read those books then I was about reading stories in my English class.
How about this: "In fact, those books were more interesting that the stories read in English class"
The books gave me specific tips on how to clean the tank, enhance the color of my fish, and which foods are best forfeed each type of fish.
@Nanncy22: You were kind to help this fellow out in this essay. Although you made a few mistakes yourself, don't worry. We can learn from each other's mistakes. :)