The fishnet thing is a running gag among Chinese military/defense related forum. It's basically a comical counter against the so-called "China Threat Theory" that's popular among WASP nations. So basically, an example would be:
A WASP nation like Australia reacts to Chinese amphibian task force fleet visiting Australia port like: "OMG, the communist invaders are at our doorsteps!"
Chinese people reply: "calm down, that's just some high-tech fishing boats we build! Don't be a chicken!"
And this running joke pretty permeates to every thing military in China:
J-20 is just a large agricultural drone for spraying pesticides for our Chinese crops.
ZTZ-99 is just an agricultural tractor for plowing our Chinese rice field.
055 is just a high-tech ocean fishing boat for catching fishes deep in the middle of the Pacific.
001, 002, and 003 are just a large whalers. (oops, the Aussies will be double pissed at this one!)