A blind character who is mistreated or neglected by his parents was an adequate introduction. However, I do feel that there is a large amount of information about your lead character missing. For example, how old is he? How long has he been blind? An introduction helps your reader tremendously get a feel for your character and how he feels about himself, the world around him, and the people he interacts with.
This was a great idea for a story even if it is basic. There are many ways that you as a writer could vastly improve this plot with elements relating to your characters. Developing a character is a writer's greatest asset for the simple reason that it allows you, the writer, to understand how a character feels or reacts concerning different things.
I'd have to say that the dialogue here was what had your characters the most developed. It showed that Hikaru wasn't much of an animal person (i.e. the comment about "it's just a fish") and that he was probably frustrated with his blindness; Sakura was a soft-hearted person who also spoke her mind; and that the two liked to tease and argue with each other like good friends. Still, you might want to add more dialogue next time. It helps you get a better feel for your characters when they converse whether the topic is important or just gibberish.
You did well enough on grammar. There's really only a couple of things that I'd like to point out.
First of all, don't use the Enter key so much. The only reason you should do something like this is when characters are speaking. Otherwise, put sentences into a paragraph until the subject changes such as when Hikaru is talking about himself being blind. All of that should have been in one paragraph that ended when he met up with Sakura.
Secondly, try to extend your sentences so that you don't have so many choppy lines. One sentence is a complete thought. I'll give you an example:
And then... I heard Sakura's light, gentle footsteps and soft breathing approach.
And with her was a tiny Burmy. Her only pokemon.
Those three sentences could have been made into only two.
And then I heard Sakura's approach from the light, gentle footsteps and soft breathing. She was with her only Pokemon, Burmy.
Try rewording your sentences so that everything can fit into only one or two instead of three or four incomplete sentences. Also, run a spelling & grammar check; it helps a great deal!
I'm afraid that detail is what you lack the most of. I couldn't get into the story at all because I didn't know anything. The thing you described the most was that he was blind and the story seemed to focus only on that fact. You did describe in one sentence how he relies on his other senses. Show
it! He could have been able to tell if there were trees if he could smell them. The sound of the leaves rustling, the Magikarp splashing, the deafening of sound itself when he went underwater could have all described his surroundings and what he was going through. Even if he can't see Sakura, I'll bet she had a natural scent to her or a tone of voice when she talked. You don't have to use only the sense of sight for a character to be able to describe his surroundings.
There was little to no battle other than him throwing a rock. I understand that he has no Pokemon of his own and that Hikaru cannot see, but why not have Sakura and her Burmy battle the Magikarp?
The length did indeed meet the character limit, but it could have been so much better if you had added detail and didn't simply chop up sentences.
Outcome: Magikarp not captured.
I realize that this was your first story, but I'm afraid that this story does not fit the criteria for even an easy grading. That's okay! You have a great idea and I'd love to read this story! Here are some tips you can follow:
-- Try to add more detail. Describe the smell, sound, taste, or feel. Vibrations and the air are wonderful examples that you've already implemented! Try to use just more than that to give your reader an idea of his surroundings such as the time of day, where he moves, where other characters move.
-- Don't use so many sentences. Remember that a single sentence is a complete thought. You don't have to chop up your sentences to describe one thing and then another; reword some things to describe it in only one or two sentences. Also, don't over-do it on the enter key
-- Add more battle and plot. Take an idea or two of what might or could happen to your characters, roll with it, and see where it leads your characters! Experiment!
These are just some suggestions and ideas. You have a great idea, it just needs a little work! Put a little bit more effort into it and it will pay off well! Once you've fixed it up a bit, PM me for a regrade either on AIM or here on PE2K! I'll be glad to help you out in any way I can. If you're still confused, check out the How to Write Stories
thread to get an idea of what can help you make your story better!