Receiving bugs/fish from villagers?

[g u a v a]

So I'd asked if there were ways to get different fish/bugs without catching them yourself and I'd been told that you couldn't. I just gave Lolly a piece for her house and got her blue marlin in return. I'd already caught one myself so I'm wondering if this type of thing only happens with fish/bugs you've cataloged?

 

[Camillion]

If you give furniture to a creature inside their house and they replace their fish/bug with them I guess you'll get the fish/bug? I think it happened once x3

 

[Chibi.Hoshi]

If you give furniture to a creature inside their house and they replace their fish/bug with them I guess you'll get the fish/bug? I think it happened once x3

Yes, but its uncommon.

If they ask you to replace a bug/fish in their house, if they are inside their house and you give them a replacement. Chances are they may give you the fish/bug in return.

This has happened to me a few times, and it is somewhat useful. Say if you have one player who caught the fish and give it to the villager, another player replaces the villager's fish and gets the fish in return. I've had this happen. It makes me think what would happen to the player if that was their final fish/bug.

 

[Punchyleaf]

I have kiki that brown piano, forgot the name of it and in return she have me the arapaima I wanted from her since I didn't have it and was being lazy about catching it lol
She was in her house when she asked for new furniture so I just gave her the biggest one hoping she would give me the fish. Thankfully she did.