1. Banish Sentinels is needed. (Name is linked to how to earn this spell).
2. Use Winnow spell to remove all fish but either storm or death. There are more death fish than storm, so death would be more logical. So remove all except death fish. ( Name is linked as how to learn this spell).
3. Use a rank 2 death lure and catch every fish.
4. Once you used all your energy stop and wait until the next day and start again.
5. To receive the quest for Dragonspyre fishing, you must finish Grizzlehiem fishing and be level 15
The reason you remove all fish except for one type is, this makes it so you use less energy not having to check schools, also you know the school so less chance of miss using the right lure. You can fish for chests using the storm school though you have very few fish. Go with which ever fish school there's most of. This can be used anywhere in Zafaria. Make sure you check to see which school of fish there's more of in that area.
If you're not actually good at catching fish. I suggest go to the commons Wizard City, keep testing behind Zeke until you can catch every single ice fish, without missing. Fishing does take a bit of patience to hit that space bar at the correct time. Lure has to be underwater, there's also a sound it makes if you have your sound on.
Hope these tips help.