How to get energetic fish
Right after the start of the Evil Emperor Frieza arc, you'll have access to a Turtle at Kame House sub-quest that will ask you for a series of items. However, one of those items requires some sort of back door to get it, forcing you to find energetic fish.
This trade quest begins with Turtle asking for 6 eggs, 7 rice, and 1 royal tomato. The first two items can be found quite easily, but Royal Tomato will take you to a farmer who asks for 10 Energy Fish in exchange for the Royal Tomato.
There are two different areas you can research to get them right now, although one is from a subquest that only provides you with one. This subquest can be found near West City where you meet Emperor Pilaf and his gang. For defeating some robots that attack them, you will be rewarded with an energetic fish as part of the "Pilaf's Gang Plan" sub-quest.
Our much better option returns to the South East Islands region with Kame House. Quickly travel to Kame House and start heading northeast, although the map doesn't seem to have anywhere other than Kame House at first. The map will expand and have a lot more, so head to the region's most northwestern island.
When you start to approach, you see a message from an NPC that says "Energetic Fish Mother, Baby" or "Stupid Energetic Big Fish". Speaking to him, you will discover that energetic fish are found under flocks of birds flying above the water, which you will notice that you are in the distance.
Fly to where these birds are and dive into the water to find schools of fish that each swim around an orb. Swim through these fish and grab the orb automatically, some of which will provide you with energy fish. You may have to leave the area and come back to learn more, but this is definitely the fastest way to grab the 10 energy fish you need.
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