Bhav of Thandhul Matsya and cause of Aayu bandh to 7th Narak

Jai Jinendra,

I have a doubt regarding the Jeevas in Swayamburaman dweep/samudhra.
I read in a book (don’t remember if its Moksha Marg Prakashak or another Dravyanuyog Shastra) about the small fish called Thandhul Matsya which lives in the ears of the Maha matsya and does instense paap bhav due to which it binds Aayu to 7th narak.

Recently, I was listening to pravachan about Madhya lok and in that it was mentioned that the outer Swayamburaman dweep & samudra are having Karma bhumi similar to Pancham kaal always.
As we know, in Pancham kaal, Jeev don’t attain highest Samhanan (Vajra-vrushab-narach) during this time. And also it is known that only the men/animals with highest Samhanan can do such intense paap that will cause them to be born in 7th Narak.

So I don’t understand how the thandhul matsya can have Vajra-vrushab-narach samhanan when there is 5th kaal prevailing there.

Please clarify if anyone knows and any reference to Shastras would be good.