I wrote this on Vanguard's forums years ago. Fishing is included in many MMOs as a bonus; but when it is, it's about as engaging as tying your shoes. It doesn't have to be that way. Anyway, my old post:
I think fishing is an area where some realism could make it a whole lot more fun. Now I haven't done much fresh-water fishing and I've never fly-fished, so I'll leave those to someone else to work out. But I have done saltwater pole fishing and spear fishing, so...
Give us different types of poles, lines, weights, baits, etc. There's only a point to this if you make fishing into something that involves practice and strategy.
When fishing off a saltwater shoreline, you have to monitor the tugging on your line very closely. The trick is that the waves and the current tug at your line too. So you often have to use experience and luck to discern when a fish is nibbling at your bait and you need to yank back on the pole to hook it. Sometimes, you'll mistake a wave or current for a nibble and you reel in your line to see the bait still on your hook. Other times, you reel in your line because it's been sitting there a long time...and sure enough, something stole your bait (damn you!).
A thicker pole won't break on you, but you also lose some of your ability to feel what's going on with your line. Stronger line is always better, just more expensive and often unnecessary. Weights are used to keep your hook and bait from being tossed to the surface by waves and currents. But you don't want to use too heavy a weight or your bait will be sitting in the mud...so there's a lot of wisdom and guesswork involved in picking a weight (assuming the strength of waves and currents on that shoreline vary). I can't say I ever used artificial lures (they don't seem to work very well with saltwater fishing).
Baits are a fun part of fishing. You could just use the shrimp, squid, minnows or whatnot you bought at the store. You might use your last catch in hopes of grabbing a bigger fish....perhaps cutting it up into small chunks. There could also be room for experimentation. My cousin, brother and I liked to catch and use sandfleas.....small crustaceans that burrow into the shoreline. In an MMO, it would be very cool if players could experiment by catching creatures like that and using them for bait. Catching sandfleas isn't always easy, so catching bait like this could be it's own mini-game.
Here's where all of this comes together.
Give players some sort of visual and audial means of detecting stress on the pole and line. In real life, I fish most by feeling movement....but in a game, you could watch the pole bend as well as watch a meter that simulates the feel...and you could hear the pole creak I suppose. A series of quick jerks usually means you've got a nibble...though not always. The player would also have to watch how the jerking relates to the waves. When a wave comes in, the part you don't see underneath is going the opposite direction and tugs at your line. So being able to see where your line enters the water is important.
If you put on too much weight, your bait will sit in the mud or get picked up by bottom-feeders (which could be good, if that's what you're fishing for). If you put on too little weight, your bait will pop out of the water or hang near the surface (which, again, can be good for particular fish).
If you use a thicker pole, your feel meter isn't as sensitive and your pole won't bend as much...but it won't break. And vice versa.
Different baits will attract different fish. Also, different baits can withstand different amounts of waves and tides. So if you didn't have wave variations in the game, you could use certain baits over again 3 times while others could be used 5 times, etc. You could have bits of shiny metal as spoons (heck, i imagine they got that name because people used to use real spoons; so why not do that?). With spoons, you're constantly casting and reeling in so the bait stays near the surface (so it can shimmer in the light) and simulates a swimming fish. In deeper waters, catching fish in the same spot for a while might attract sharks from all of the blood when you hook fish, so there's such thing as accidental bait. A funnier example is when people in small boats tie a big fish along the side (because they don't have room in the boat) and a shark will grab it. A Great White did that to some poor folks in the Gulf of Mexico years back and nearly tipped them into the water with it.
Lastly, I'd like to see fisherman catch a lot more than fish in a game. EQ had it so that you might fish out junk fish or just plain junk. In reality, that happens a lot (saltwater catfish, seaweed, driftwood, etc). But you also might catch rays (some sting you, some shock), eels (morays are poisonous, others shock you pretty badly), crabs (the little punks hang onto the line with their claws and let go at the shoreline), starfish and sand-dollars and urchins (no, they don't tug the line), octopi and squid (those suckers can hurt...and some squids have claws in every sucker), sharks (yeah, you're careful taking them off your line, haha) and plenty of other things. Plus, if it's a fantasy game, why not throw in a lot of stuff we've never seen before? Look at prehistoric fish (from the Devonian and Ordovician periods in particular) -- very different from today's sea life and very cool.
And I'd like to see fisherman get stung, bitten, shocked, and such on occasion. Most of the time, it should be nothing serious. Saltwater catfish in the Gulf of Mexico have stingers in their fins filled with a poison that makes it hurt more. It would be funny if something like that or a crab had the chance of hurting a character and making them hop around uncontrollably for a little bit. Other stuff, like highly poisonous fish (moray eels) and shockers could potentially kill you. I think it would be a cool addition if players could (rarely) die from fishing. Wouldn't that be a great tale to hear in the tavern one day?
But before I conclude my book of virtual fishing(TM), let's talk spear-fishing and deep sea fishing.
I haven't done underwater spearfishing (freediving) -- that's a whole other topic. But I have done spearfishing off the shoreline. It would be another cool mini-game. The screen turns into a first-person view, looking straight down into the water (perhaps seeing your bare feet below....different for every race (troll feet are nasty, I imagine). Different fish would move at different speeds across your screen. Plus, the water refracts the light a little bit, so you have to aim a little to the side of where you're seeing the fish (optional feature). If you've ever played the game Amazon Trail, that's basically what I'm talking about and it's very fun.
My cousin once caught a stingray with our spear. It was our first real catch with it, so it took a moment to recover from the shock before we realized the pole was moving out to sea!
As for deep-sea fishing. It would be cool if a game's boats could go trolling. You drag fishing lines behind you and fish bite the moving baits. It's simple and easy, and probably a great way to entertain players while traveling on boats. Some might even do shark-fishing with chum.
Just think... If I was more familiar with fresh-water fishing and fly-fishing, this post would have been twice as long. ;) I think most, if not all, of it can be worked into an MMO to make fishing more fun and create a couple quality mini-games. You'll notice that the pole fishing system in particular introduces personal customization, strategy, and reward for individual experience.