I'm translating this show called "Chef Abroad", where they go to New Zealand and meet with a Kiwi Chef and fisherman. Anyway, they're by a river called Green Stone river and they say the following.. which I can't understand

* Brownies are cunning
* Lazy are cunning
* And the rainbows are effervescent., let's have a party, disco biscuit sort of fish.

Can anyone tell me what on earth they're talking about? Are they talking about certain types of fish?

Thanks in advance for any help I can get.
Hisham

Brown and Rainbow are trout, I would imagine, Lazy I have no idea. "let's have a party, disco biscuit sort of fish"...I'd like to know what this means too!