Right. So, something memorable...

[Byleth rubbed his jaw in thought. What this person thought memorable was highly likely different to what he thought memorable: a unique fighting style, maybe, or a particularly dangerous foe to watch out for on the battlefield. In general... fish, maybe? Fish were always memorable.

But who was he to show it to? He didn't see where the moonbug came from.]

I'm not quite sure what they would deem 'memorable', aside from catching a particularly big fish...