My dorm---two tortoises

I have two tortoises which one is male and another is female in a transparent fish tank. I put them on my desk with a desk lamp which can offer warming. They are the species come from Brazil, for this reason I have to worry about the chill here can kill them. The first day take them back from supermarket I picked some rocks and aqua-plants from a lake and built a lovely habitat, at least in my concept, for them,
I am definitely a tortoise maniac. Back to my high-school time, I bought six tortoises from market and raised them at a miniascape which is consisted of a big fake mountain and many living aqua-plants. What surprised me was that these adorable pets chose to suicide by jumping from the top of the mountain. As the miniascape was laid out of the window box, these tortoises were directly flew away from the fifth floors. I still feel sorry for them today.
So, I swear to the tortoises which accompanied me ago. I will try as I may to take care of these two tortoises I have now.

I will break down your errors and try and explain them my corrected sentences will be bolded.

I have two tortoises which one is male and another is female in a transparent fish tank. I have two tortoises in a transparent fish tank. One is male the other female. Not bad. You wrote a run on sentence. You can break English sentences up into smaller chunks.

 I put them on my desk with a desk lamp which can offer warming.I put them on my desk with a lamp for warmth. Okay. You don't need to mention the lamp as a desk lamp however this isn't incorrect so much as it sounds odd.The lamp offers warmth, which is a noun. Warming is a verb and as such can't be offered.

They are the species come from Brazil, for this reason I have to worry about the chill here can kill them. They are a species that comes from Brazil. For this reason I have to worry about the chill here killing them.  Ah the tricky use of articles. The is the definitie article in article. When you use it in this case it implies that the tortoises come from the ONLY tortoise species in Brazi which simply isn't true. This sentence seems to run on like your first. Additionally the you could worry about the chill here which can kill them although I prefer my initial revision better. 

The first day take them back from supermarket I picked some rocks and aqua-plants from a lake and built a lovely habitat, at least in my concept, for them,

The first day I took them from the supermarket I picked some rocks and aquatic plants from a lake and, at least in my opinion, built a lovely habitat for them. This sentence is NOT a run on it's just long. If you say "take them back from supermarket" it implies that you had them at first, took them to the supermarket, and then took them back! I assume you've been taught English as opposed to American English so "aqua-plants" would probably be correct. Generally you would use opinion as opposed to "concept". Your interjection of thought (the "at least in my concept") needs to come before your second verb phase otherwise it disrupts the completeness of the thought.

Back to my high-school time, I bought six tortoises from market and raised them at a miniascape which is consisted of a big fake mountain and many living aqua-plants. Back in my high-school days, I bought six tortoises from market. I raised them at in a miniascape which consisted of a big fake mountain and many living aqua-plants. Again a run on sentence but structurally more understandable than the first two. After realizing you are using English, instead of American English I tried to preserve English grammatical style. The first half of your first sentence could be written as I wrote it or "Back when I was in high-school". Both would be correct. If you say "back to my high-school time" it implies that you already were discussing when you were in highschool, changed the subject, and then returned to discussing when you were in highschool. Also if you do something "at" someplace it generally implies that the location is a building. If something is done "in" someplace it can be any size.

As the miniascape was laid out of the window box, these tortoises were directly flew away from the fifth floors. Since the miniascape was laid out near the window, when they fell from the mountain it was a five story fall. Okay this one was tricky. I understood what you were trying to convey but it was very confusing to read. This version would make more sense.

Overall it's pretty good. I know I couldn't write a similar account in Chinese.