Fish purity

Hi,
the wiki says that Frontier & Wilderness caps fish purity.
Does that mean that levelling up my F&W will increase the purity of the caught fish?
What's the difference in using a common earthworm or a bait?
Can I get every fish with the classic fishing rod or do I need the fishmaster 1600?
Do poles have any effect or is it only the lures?
I really need explanations because the only fish I'm getting is an angel-winged seabass
the wiki says that Frontier & Wilderness caps fish purity.
Does that mean that levelling up my F&W will increase the purity of the caught fish?
What's the difference in using a common earthworm or a bait?
Can I get every fish with the classic fishing rod or do I need the fishmaster 1600?
Do poles have any effect or is it only the lures?
I really need explanations because the only fish I'm getting is an angel-winged seabass
