Galapagos achievement in No Man's Sky

The way I've been scanning fauna, on planets that do actually have animals (be sure that the planet you're currently looking for animals on, does indeed have fauna), is solely by running around with my scanner and looking for red blips (which indicate that it's an animal species/variation you've not yet scanned). The best planets that you can find to scan are ones that have ideally only 5 species to scan. It helps speed up the ability of hopping from planet to planet faster since you'll, more than likely, find at least 2-3 right off the bat as you land for the first time on said planet. But there's nothing wrong with 10+ animals, just may take a bit longer if you're not looking in the right places.

Some red blips could actually be semi-modified versions of already scanned fauna, therefore not counting as its own species discovered. Be sure to remember this.

Animals on all planets, on planets that do indeed have fauna, can be found in many locations. During the day, land species could be roaming around under the sun as well as in caves, some during the night alone. Flying species are always found during the day, with some from the day at night too. What I've noticed, and heard about, is that there are currently no flying species solely who come out at night just yet.

If you're on a planet that has water, about half - if not almost half, of your species could be found underwater. You need to be completely submerged under the water for the animals to spawn in and be able to scan them, otherwise the game only spawns land and flying species. If you are scanning animals under the water, be sure to be a good ways down under. Otherwise you'll gradually float back up; and if you're too close to the top of the body of water, as you're beneath it, it'll sometimes de-spawn the aquatic species you're trying to scan right in front of you.

When you finish scanning every animal on your planet, hit the button, and scroll over to the discoveries tab with or , if you're not already there. At the top right of the tab, you'll see a list of the Fauna you've already scanned and a silver paw print. Hold over the paw print. It'll turn golden, rather than silver, to indicate that you scanned all fauna on that planet.

You're now a step closer to getting the achievement!