Betta Fish: My girl died because of me.

So, I got my girl from an online breeder a few weeks ago. Sure, she's not perfect and she had severe Popeye eye when she arrived, but I tried to give her the best life she can have now that she was here.
For weeks she lived happily in a 13 gallon tank with driftwood and some hornwort, and I was planning to make her a full blown aquascape. And today I was really happy because my packages filled with plants, soil, lamp etc has finally arrived.It's time to make a heaven for her to live.

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So I emptied her tank, taking out everything as well as cleaning them. I put my girl in a bucket filled with her tank water and leave her under the table as I prepared everything. But when I'm putting the soil inside, I glanced to her bucket and found that she was not there. I searched for her all along the floor and found her far from her bucket, near my foot.

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She was dying. Her fin torn really bad, I think she jumped and I accidentally step on her while going back and forth to fill the tank with soil. She never jumped before in her tank, at all. I frantically put her back into the water. She would flap her fin a few times and gulp for air for the last time in front of me. That's it, I accidentally killed my girl.

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Now I just spent an hour crying while continuing to finish my gonna-be-empty-tank. I know time our time together was so short, and she's not a super expensive betta or something. But I love her, she's the most friendly betta I have ever have. She would swim to me everytime I check on her tank, I don't think I can find another fish like her.

I'm truly sorry, biru.. So sorry that your mama can't give you the happiness that you deserves….