What Kind Of Catfish/shark Is This?

[fish-r-fancy]

Hi some neighboor hood kids played an evil joke on my friend and threw a shark/catfish in my friends koi pond. This shark/catfish has killed several of my friends fish that are over a foot long, bigger than the shark/catfish! The shark/catfish is between 6-12 inches long it's hard to tell with it being in a koi pond and all. We tried to net the fish out and weren't very succesful, my friend ended up getting poked by the fish. it seems that the fish had some kind of spike on its head. I think clown loaches also have these. The fish is beautiful it is green,gold and has a little orange. We took the fish to a fish store and they said they didn't have a clue what it was. They thought that it was a catfish but said it could also be a shark. They looked threw all of there books and found nothing. Does anybody know or have any idea what kind of fish this is? Thank you.

P.S sorry to post twice but I realized that my first post was in tropical chit chat

The fish also has a black spot on its side.

 

[babybell911]

some kind of sturgeon sterlet ,maybe?

 

[fish-r-fancy]

Oh sorry but I already found out that it was a bullsye catfish and it has tons of other names too.