Hi, I've gotten a few questions about this so I wanted to post a quick guide for the navigation of the website. (Click the pictures to get a bigger shot).
At the top, there is the ranking page (circled in red) and the report center page (circled in green).
On the left side is where you click for the fish server registry files so that fish server will show up on your gateways in starcraft.
If you click the rankings button,you get to a page like this:
On the left, (circled in yellow) are melee ranking, ladder ranking and points ranking. Most people are probably interested in the middle one.
Alternatively, you can just click this link: http://www.fishbattle.net/rank_ladder
If you want to search for rankings, just scroll through the numbers    etc.
The report system is different from iccup from what I can tell. I might be wrong but it seems that if your opponent is caught intentionally disconnecting, then it is a 30 day ip ban for him from the server. However, you do not get your ladder points.
For reporting, you need to type in /g enter during the game and take a screenshot. This shows a little blurb that basically proves that you are playing a ladder game on fish server (as opposed to west or brain or something like that). If you can't, then drop him and do /g and catch the "opponent has dropped from the game" line in the screen. Also take a screenshot of the drop screen. If you lose connection to server (say if the server reset at 4pm) you can't do /g. Then click the Report Center button, (7th from the left at the top, circled in green in the above picture).
You need to be logged in and your password must have numbers as well as letters (you can change it on the server and it will be changed on the website in a few minutes).
You get to this page:
Click the 2nd icon circled in blue (basically report here)
You get to a page that looks like this:
On the scrolldown menu, simply put, it's
"complain against admin"
Click the 4th one for disconnect and for opponent id, put their id
for title, just copy paste this: 상대가 디스했습니다
For description put this:
제가 이기는 상황에서 상대가 디스걸었습니다.
Click the file upload button (circled in black) and upload the replay of the game. Also upload the two screenshots that you saved.
Also if you're curious, the numbers near the top of the screen say that there are 32,810 people playing in 8,089 games on fish server at the moment.