Last night I got up to level 35 with fishing. A new fishing rod to catch up to 300 (and something) fish in whatever colour fishing holes. I find the colour of the fishing hole does not make a huge difference. A gold fishing hole will still have plenty of white/ silver fish. I have been at a gold fishing hole with a group of people and caught nothing but white fish. If you are lucky enough to find a gold fishing hole and have it all to yourself, VERY LUCKY, you have a better chance of catching epic and legendary fish. Otherwise, I have actually caught more epic and legendary fish at the common white fishing hole than the fancy coloured ones.
Frostvale was my favourite fishing spot so far. But, as you level up the value of the fish you catch goes down. So even though I really liked fishing there, there wasn't much point to catching anything (unless I didn't care at all about levelling up).
Happy Fishing Sunday!