Board Thread:Episode Discussions/@comment-1181222-20171025100708/@comment-26369387-20171025102730

Oh, look at that, worthless filler characters were worthless. Didn't saw that coming at all...

Anyway, "Ninja Art: Snakehead" would be 忍法・雷魚, Ninpō: Raigyo(lit. Ninja Art: Lightning Fish), where "raigyo" is Japanese name of snakehead. So basically it's pun.