There are 16 species of fish in the game, you need to catch 15 for this achievement. There are 3 rods in the game but you only need to use 2 for the achievement, the simple fishing rod (the one given to you by the fisherman) and the excellent fishing rod (aka the most expensive one). You can catch 7 different fish with the simple fishing rod and 9 with the excellent rod.
You get the simple fishing rod by bringing 6 moths to the fisherman at the lighthouse (you'll need to unlock the technology to catch moths). Moths are caught when picking up flowers during nighttime.
All fishing spots locations:
- The dock on the beach/sea. Hard to miss.
- The small pond N-E of the village.
- The waterfall to the left of your house. You access it from the other side of the bridge you need to repair past the church.
- The very top of the river on the left of your house. It's to the right of the marble quarry.
- The last one is in the swamp. This one is a bit tricky to pinpoint its location so bare with me, go down past where you need to build a small bridge that leads to Cloto and then make your way around the swamp.
Here's all the fish you can get with the simple fishing rod (location / range / bait type / %):
Anchovy: sea / near / no bait / 100%
Frog: pond / near / butterfly or moth / 100%
Tilapia: pond / middle / butterfly or moth / 100%
Perch: pond / far / butterfly or moth / 100%
Gudgeon: pond / far / no bait / 100%
Bream: river / near / no bait / 100%
Eel: swamp / near / no bait / 100%
...And with the excellent one:
Sardine: sea / near / no bait / 74%
Tuna: sea / far / gem lure / 98% during the day
Goldfish: sea / far / gem lure / 5% at night
Silver Crucian: pond / far / gem lure / 100% at night
Carp: waterfall / near / no bait / 100%
Salmon: waterfall / far / gem lure / 67%
Gold Crucian: river / near / anchovy or gudgeon / 16% during the day
Pike: river / near / gem lure / 100%
Sturgeon: river / middle / butterfly or moth / 100%
A few fishing tips: Fishing in this game can be a bit tricky to understand at first, but once you get the hang of it, it becomes much easier. To fish, you need to wait until the fish bites (takes around 8 seconds for most fishing spots). Your window of opportunity to press A to reel is quite short so you need to be real quick, if you're a bit too late you'll miss and have to wait a bit more until the fish bites again. As for the mini game itself, you need to keep the fish icon in the yellow bar, which is sometimes a pain in the back end, for this simply hold A and release it to keep the yellow bar on the fish. This mini game seems daunting at first, but trust me there are way worse fishing mini games out there (looking at you Oceanhorn). The faster you complete the mini game, the easier it'll be as the fish tends to move a lot (and gets more difficult) when you don't complete the mini game quick enough.
Eating fish-related food before fishing can help a lot. Fish nuggets give you more time to reel the fish after it bites. Baked fish and fish soup both make the mini game a little bit easier (by making the fish move slower).
Big up to Failure Online, Jacky chaud and beMoD for pointing out the changes introduced in the last update.