China has a long history of skipping the research and development stage when it comes to fielding new military aircraft, instead opting to purchase or outright steal aviation technology from peers and competitors like the United States and Russia. Much ado about China’s fifth-generation J-20 and forthcoming J-31 platforms has already been made in the media, thanks to these advanced Chinese programs being based directly off of stolen plans for the F-22 and F-35; plans provided to the Chinese by a businessman name Su Bin — who is now serving a 46 month sentence in federal prison for the crime.

However, the United States isn’t the only nation with something to complain about when it comes to China stealing their way to keeping pace in the skies. Although Russia has happily (and sometimes not-so-happily) sold China production lines for a number of their air platforms over the years, China’s J-15 Flying Shark isn’t among them. Despite money never changing hands between the two states, however, there’s no denying that the J-15 is a copy of Russia’s Su-33. China wanted the Su-33 (Russia’s carrier version of the Su-27) for its Soviet sourced Liaoning aircraft carrier, so when Russia didn’t act interested in playing ball, China went around them to the recently independent Ukraine. They purchased a T-10K-3 from the Ukraine government, which was effectively a prototype Su-33, and quickly set about reverse engineering it.

The result was the J-15 — an air platform that bares a striking resemblance to the Su-33, but as is often the case with Chinese copy-cats, the similarities don’t seem to extend to performance. While the Su-33 is widely deemed a capable fighter, the J-15 has suffered repeated issues and failures, prompting many within the Chinese government to postulate that the forthcoming J-31, rather than the J-15, should be the aircraft flying missions aboard China’s two carriers currently in development.

Now, Russia has decided to chime in on China’s apparently failed effort at fielding a Su-33 imposter. Sputnik, a Russian state-owned media outlet often used to advance Moscow’s narratives, recently addressed the J-15, citing perceptions of the aircraft from within the Chinese people and offering little pity for the program’s failings.

“The Asia Times noted that Chinese media has disparaged the plane in numerous ways,” Sputnik wrote, “including referring to it as a ‘flopping fish’ for its inability to operate effectively from the Chinese carriers, which launch fixed-wing aircraft under their own power from an inclined ramp on the bow of the ship.”

“Years ago the Chinese decided to save some money and, instead of buying several Su-33s from Russia for their subsequent license production in China, they opted for a Su-33 prototype in Ukraine,” the outlet quoted Russian military analyst Vasily Kashin as saying. “As a result, the development of the J-15 took more time and more money than expected, and the first planes proved less than reliable.”

Of course, these criticisms are a bit ironic, coming from a nation that made a habit of directly copying western technology throughout the Cold War. To find direct evidence of this, one needs to look no further than the defunct Buran space shuttle program: a Soviet space shuttle that was modeled directly after America’s fleet of similar vessels but only managed to conduct one unmanned flight before the program lost funding.

China and Russia recently participated in a series of large-scale military exercises together, prompting concerns among some that the two nations are developing closer ties in an era of heightened tensions with the United States. However, China also deployed spy ships to monitor Russian naval activity during the training, which alongside Russia’s new remarks regarding stolen technology seems a bit like both nations are eager to remind one another that they may have a common enemy in America… but that doesn’t make them friends.