I'm completely new to fishing, never really done it before and I have a question about ranks of fishing (Novice angler, neophyte angler etc). I am currently fishing in Wizard City but the highest level world I can go to is Dragonspyre, if I try fishing in Dragonspyre, will I not be able to catch any fish there due to my low rank?
You'll still be able to catch fish there. You'll want to do the Dragonspyre fishing quests. They'll unlock some more utility spells that are extremely useful.
I've had a high fishing rank for quite some time and haven't paid attention to whether or not there are restrictions on fishing spells in the higher worlds where you can't buy them if you're not a certain rank like some crafting recipes. If there are, that's the only way you'd be restricted is in obtaining better fishing spells. Otherwise you can catch fish anywhere you find them regardless of your rank.