problem to create a new Fish

First things first, sorry for my bad english.

I tried to create a new “sort” of fish for my server, for special events and something like that. Now the most works properly and I can create and spawn the fishes without any problems. The only thing I need to know where I can create the “weight- level” who fishes like the Coelacanth have (0x3,—,1x3 etc.).

I tried my best and modificated everything like the coel and searched on the Internet for multiple hours but it won’t work. Has someone any idea where the fishes like the coels are defined or something like that?
Any suggestions or help would be appreciated.

Thanks Jyrkoon