Fishing Sim World Gigantica Road Lake

Hi all

I have caught all the Boss carp over 5 times each with the exception of one which I cannot seem to catch. The boss I am missing is called 'Unamed Common'. Can anyone help me with catching this one? I'm beginning to think it doesn't actually exist.

Many thanks in advance

 

It's there, persistence is key, I swear. Caught a few of them 10+ times, just have to keep farming.