Anyone knows what i would get?

[ponitboss]

What kind of fry can I expect if I cross a fantail goldfish with a oranda goldfish?

 

[sto0ka]

You'll get mix probably. They all carry same gene of wild/normal/comet/basic goldfish.

It's kind of similar to dogs xD. If you crossbreed pure sort with mixed, offspring will have more characteristics of pure breed since genes are stronger and pure.
Genetics are weird stuff, I'm no expert so none of this is 100%

Now in your case you have two already engineered fish and they have same genes of regular goldfish + extras like wen, fantail, telescopic eyes etc.
My guess: You'll get some fry that will grow wen, some of them will have fantail, some will be regular goldfish.

I'd love to crossbreed different fish xD (Like Betta and Notho Killies to get real killing machines)