Sorry, but I have a fair bit of criticism for you, so let us begin. I'm guessing that this piece is a continuation of another which explains a lot things i didn't understand.
At the very beginning, i was like 'okay, it's a human' 'but wait, it's an animal!' 'no wait, i have no idea what it is!' 'hang on, this is all underwater?'

I felt like your sentences were far too descriptive making the flow choppy and confusing, but there wasn't enough actual description of the environment and characters so whenever someone spoke all i had was a blig blob in my mind. Eventually i figured out that they look kinda like zoras from Legend of Zelda, but then they only had a tail and no legs. Essentially, a more up-front discription would have been very nice. Oh yeah, and i have no idea what the flipping fudge a hull-runner is. You also had the annoying tendency to include unnecessary slashes and 'i's whenever you italicize.

Once i got into it and discovered there was a plot and identafiable characters i found myself enjoying it, but by that time the story had come to an end. Personally, i only found the human's behavior unconvincing when he is first rescued and an alien head pops out of the water and starts talking to him and he's all like 'sounds good. take me for a ride, fishies!'

Okay, i know that was pretty harsh, but i'm having my period and am not in the mood to lay on the whipped cream.

This was an excellent piece, the diver part of Czeran culture, the imperial political agenda, the human-Czeran relationships both legal and illegitimate, and the Czeran characters in particular, extremely well-developed and presented in just the right doses. The underwater setting is realized in a very realistic way. The only thing bothering me is the human, whose information Launu bases his next move on. He's not very believable, and until Launu gleans what he can from his account, I thought he was lying. If he was, however, the way the story continued made me believe the point of that characterization was for Launu, that with his analytical mind, he's able to sort together fragments of the truth and piece together fairly accurate information quickly. It did not leave me feeling there was a reason for the human to behave so odd, even after being rescued. It's a small thing, though, with many possible explanations (a less familiar human culture, for one), and I guess it doesn't matter too much to the story. Overall, I really liked this one and hope to learn more about it in the future.

Very enjoyable and well-written piece, in my opinion. I think you do very well with description, and wouldn't mind having more of it for this piece. A part of me wonders exactly how Launu's people look, but another part of me feels that you have the right amount of description--just enough to formulate my own image of the people, and not so much that any freedom I have in my interpretation isn't ruined.

And at first I felt like the piece ended too quickly and without enough punch, but the very last line actually does a good job of ending the piece. I do wonder though, if you could add a little more to this ending, and see where that takes you.

Also, I actually think the piece would benefit if you described the ship wreck in even more detail. It seems like such a scene should be rather haunting, full of ghosts, even if the reason for the sinking wasn't much of a mystery for Launu and his people.

Lastly, while I think you have good characterization for most of the people in this story, the human survivor's character could use more development. I didn't find his attitude to be believable--it seemed like he should have been more shaken up than he actually was. And I'm a bit foggy, as a reader, as to the familiarity the general population of humans is supposed to have with the Czerans. Is the average human comfortable in a Czeran presence, or unsettled? I would lean towards the latter.

Also, is this a self-contained short story, or part of a larger work/world? Because I think with a few more details and more description, this could function as a self-contained piece.

Overall, I'm quite impressed.