Sometimes when I'm fishing, one different kind of fish appears (see the attached image to see a comparison).
It doesn't matter how fast I click the mouse, it always escapes, it moves ridiculously fast!
Have you been able to catch it? Please teach me the magic, because I'm strugling so much to catch that *insert something offensive here* ! >:|

I've only been able to catch these fish using the Iridium Rod with a Barbed Hook in the Tackle Slot, and even then it was pretty tough.

Edit: To clarify, the Barbed Hook kind of magnetizes itself to the fish to make it easier to catch.

I gonna give it a try!

Barbed hook for rare and fast moving fish is worse I think. They get loose from the hook too often and you cant control it easily. I use Cork Bopper and that helps quite alot. Also try to memorize how the fish moves in the bar when you suspect you have a rare one so it would be easier next time.

Be grateful that you're at least able to catch fish ;)

I caught a fish on my first try and then it was just a string of failures, I really don't "get" this mini-game (yeah, the bar has to stay behind the fish but I don't grasp the "momentum"). Fishing in Animal Crossing was easier :(

Generally speaking there are two main "methods" to the fishing mini-game that people tend to employ.

The first is the mash method, as it sounds you mash left click really fast in bursts to keep the hook bar in line with the fish. This method is useful for catching the slower moving and lazier fish that tend to just move to one spot and hover up and down slightly.

The second method is the hold method where you actually hold down the left mouse button for a slightly longer period of time to keep the hook bar in line with where the fish is and potentially where it is going to be. You want to use this particular method for the more energetic fish that move up and down more frequently, simply hold the left mouse button down to catch up with the fish, release and then hold again as the hook bar starts to drop. The reason this is more useful for faster fish is because you want the momentum of moving up or down (from either holding the left mouse button or completely releasing it) to carry through as the fish moves.

For example, if you hook a quick fish and it immediately starts moving up to the top of the bar you will want to hold the left mouse button down to quickly catch up to it and start getting the catch bar up. Hovering over it, you will want to move up and down from tip to tip of your hook bar ready for it to move again, so when it starts dropping fast you're able to just release the left mouse button and let the momentum of your bar catch it quickly. The trick then is to get used to slowing it down as it falls by holding the left mouse button as it nears the fish in it's new spot and once again centering.

It's really really easy once you get to grips with it and there will be some ridiculously fast and crazy fish that both requires you to use the holding method and the mash method in conjunction with one another.

As expected the Tackle you use can give you an edge but the two only decent options when struggling with actually catching a fish are the Lead Bobber and the Cork Bobber. The Lead Bobber will give your hook bar some weight so it won't bounce like a maniac when it hits the bottom of the fishing bar. Very very useful when dealing with the fast fish as they can go from the very bottom of the bar to the top within seconds. The Cork bobber will simply increase the size of your hook bar which will give you more room for error when trying to center on a fish.
Pupcakes mentioned using the Barbed Hook which, while it does has its uses, I definitely wouldn't recommend on fast fish. The hook bar will try to stick to where the fish is currently and when the fish is moving so fast, you'll effecitvely lose control of where you want the hook bar to be. I would however recommend it greatly for slower fish, especially if you're just trying to catch anything as the bar does not need as much management.

Almost all the other Tackle only help with either getting a fish to bite at all (if for some reason you can't get any bites) or help with grabbing the red treasure boxes that show up from time to time. The only exception is the Trap Bobber which will cause the catch bar to reduce a bit more slowly when your hook bar isn't in line with the fish. I don't personally think it's worth it as the reduction is very minimal and when dealing with quick fish, if you lose control you will likely lose the fish regardless of whether you have the Trap Bobber or not.

If you have any questions feel free to ask! This is also very useful to keep in mind. Each fish has a pattern that they will tend to stick to which can sometimes mean you know what you're going to catch before you've caught it. Memorizing whether the fish will go up or down at a given point will be very helpful in knowing when to start dropping or ascending. The faster fish will punish you for simply trying to react.

Guess it must come down to personal preference, then. I didn't feel like the cork bobber made the bar big enough to compensate for the sporadic fish movement, and I find the lead bobber worthless since I rarely touch the bottom. I couldn't catch the fast fish with either. The barbed hook on the other hand, while it is thrown off by the faster fish, it is moved in the direction the fish is headed so I know whether or not to compensate with taps or not.

I guess the real answer is try out the tackle and figure out which one works for you, as well as practicing the general fishing mechanics.

I had the same problem : First fish was easy, and then I had a long string of failures (10-20 of them without catching anything). But it finally "clicked", I got better at it, and I can now catch all the "slow - to - medium" fishes on 90% of my attempts. And the fishing minigame has become one of my favorite parts. So keep trying, and you shoud get better :)

The fishing minigame is why I like fishing so much in this game!
I'm glad I'm not the only one who finds it fun - I've read quite a bit of complaints about fishing in the Steam forum, asking the dev to change it.
I hope he doesn't!
The fish in my screenshot is one of the legendaries, so it makes sense that it's hard to catch.
It's not like in Harvest Moon where you take an useless photography of the rare fish, in this game you can sell them, and they're worth a lot.

Yeah, it's frustrating at first (especially since it's poorly explained), but then you learn to "dance" with the fish, you learn their patterns, you develop a technique (I'm a believer in the "short push" school of stardewfishing) and it becomes quite satisfying. Especially when compared to other fishing minigames like the one in Trails in the Sky, that can often be summed up as "just wait and click once when the exclamation mark appears, and then maybe you'll get something"

Yes! I love it. I'll never understand why people want it to be like Harvest Moon where you just throw your line in and auto-catch the fish, it gets so boring.

i have been trying to catch some of the rare fish the day after the game came out and i found that the fish icons movement is WAY to fast/bouncy for any of the rod, bait or hooks to compensate for such a bouncy fish icon. i have tried both the fiberglass and the top fishing rod, neither of them made a difference and the cork bobber with the top fishing rod didn't help either! sure they are rare fish but with the way the icon moves like it does it's not worth trying to catch them. if it were slightly easier to keep the bar on the fish icon to me they would be worth catching.

OK, I spent the last two days on the game (yeah, I'm postponing my IRL work for this week-end), I'm starting to bathe in cash with my farm and as Alma cited Steam, I checked one of the guide there and then:

"Keep the fish inside the green bar by holding or clicking your left mouse button/release it to drop the bar if the fish goes down to make your progress bar go up"

Wwww.......Whaaaatt? o_O I got my first fish (from the so-called "tutorial") by just doing some old-school button mashing coz I grew up on Track&Field :o) It never crossed my mind we have to actually hold the button, no wonder I always failed ^o^ Fucking "tutorial"..... :)))

The tutorial is a bit poorly-worded. I remember it saying something weird like "keep the green bar behind your fish" and thinking I had to chase the fish up the meter.

Yeah, it was exactly the same for me. I thought I had to "chase" the fish to the surface by getting the green bar under it. And since nothing appeared to work, I was utterly confused.
It took me 10 attempts to notice the catch bar filling up (or rather, in my case, emptying) on the right side, and understand I had to put the green bar on the fish and maintain it this way until the catch bar filled up.

Now, I manage to catch tuna with the fiberglass rod. Most of the rare fishes are still far too quick for me, though, but I'm getting there. :)

Yeah, it's a game of control (and fast reactions), not speed. Personally, I find it far more enjoyable this way than the old track-and-field "tendinitis way" ^^