While never-before-seen fish in Breath of the Wild have been added to Tears of the Kingdom, species from the preceding game have made their return to the new Hyrule. 
Hearty Bass are great to cook since they'll give Link full recovery. In other cases, they're used for upgrading particular armor sets.
Players may assume that in order to find Hearty Bass that they should take to the rivers or lakes of Hyrule. Ironically, players will have better luck finding them on the Sky Islands. There are two surefire ways to get Hearty Bass in Tears of the Kingdom, but getting there will require the paraglider and some stamina.
Hearty Bass Locations
Hearty Bass in Breath of the Wild could be found on Mount Rhoam or near Hateno Tower. This is not the case for Tears of the Kingdom, in which Hearty Bass habitats have been moved to the West Hebra Sky Archipelago and the Necluda Sky Archipelago on Sky Islands. Both of these places can only be reached via paragliding and with the help of Skyview Tower. However, reaching the Necluda Sky Archipelago requires the Zora Armor.
Since Link can't use Remote Bombs in Tears of the Kingdom like he could in Breath of the Wild, the best way to catch the Hearty Bass is to shoot them with an arrow. Then, dive in and collect them with A-button. Another way of getting them is to jump in and swim towards the Hearty Bass themselves, but doing this risks them swimming away when Link gets too close.
Do NOT use Bomb Flowers or Bomb Arrows to "fish" the Hearty Bass. They will instead turn into Roasted Bass and can no longer be cooked. Thus, they will lose their "Full Recovery" effect.
West Hebra Sky Archipelago
This is the easier of the two Hearty Bass locations to reach. There are three ways of getting to this island (-3887, 2787, 0709):
- Use the Rospro Pass Skyview Tower (-3684, 2343, 0233) to launch into the sky and paraglide towards the island.
- Warp to the Wind Temple and fly west.
- If players have unlocked it, warp to the Ijo-o Shrine, which is on the same island as the Hearty Bass.
There are two ponds on this Sky Island, and each one has two Hearty Bass. Make sure to check both of them before leaving. Of course, it would be wise to activate the Ijo-o Shrine, too, if players haven't done so already. This will establish a Travel Point to the Hearty Bass in the future.
Necluda Sky Archipleago
The island in the Necluda Sky Archipelago can be reached by using the Rabella Wetlands Skyview Tower. Fly towards coordinates 2112, -2621, 1263. Players will notice this island has a waterfall and that Link won't be able to land on the island from the Skyview Tower.
Go to Zora's Domain and start the main quest Sidon of the Zora. Link will then need to report back to Yona in Zora's Domain to get the Zora Armor. She'll need one Ancient Arowana, which players can get from waters on the Great Sky Island (the starting place of TotK) by the Temple of Time. Once she has this, she'll return Link's repaired Zora Armor. The Zora Armor has a special ability that allows Link to swim up waterfalls, which is what he'll need for the Necluda Sky Archipelago.
Swim into the waterfall while wearing the Zora Armor and Link will swim up to the island. The pond on this island has Hearty Bass, Ancient Arowana, Tireless Frogs, and Hot-Footed Frogs. At night, Sunset Fireflies can be caught here, too.
Where to Use Hearty Bass?
Hearty Bass has a Full Recovery and Temporary Hearts effect when cooked into a meal. Temporary Hearts are yellow hearts added to Link's regular heart counter. They can't be recovered by eating food. The only way to "recover" them is by eating another meal with the Temporary Heart effect.
The final usage for Hearty Bass is at the Great Fairy Fountains. They're required for the Zora Set (ie: Zora Armor, Zora Helmet, Zora Greaves). Players will need 3 Hearty Bass per piece as well as 5 Blue Lizalfos Horns and 3 Lizalfos Tails in order to be upgraded to level 3.
Tears of the Kingdom is available for Nintendo Switch.