If he drew a fruit modification method, he would enter a waiting period, waiting for the Hundred Beast Corps to find a suitable fruit. However, he was lucky to draw a direct transformation.
Although this means he won't have to fear water, the ability range is limited to the attributes of the five plates, and the red carp is naturally the famed Magikarp.
You can find them in every aquatic zone, though they're weak within aquatic species and might be swept away by strong currents. Still, they possess resilient vitality, adapting to various aquatic environments.
Whether fresh or saltwater, lakes, rivers, or oceans, they are present, and a well-trained Magikarp becomes strong enough to swim upstream and climb waterfalls.
Though it can't evolve into Gyarados with its strength alone, Magikarp's ability is still an ability. At least in Human-Beast Form, he can breathe underwater, essentially getting the Fishman's ability for free.
Individual variability always exists, and a trained Magikarp can grow stronger, though the process is more challenging.
He gained Magikarp's ability but didn't turn into a Magikarp, so where he can reach depends on himself.
As for whether this ability will cause trouble—
No one will care about an ordinary ability user joining the Hundred Beast Corps, even if the ability seems strange.
Who can say how many ability users are among those sailing the sea? Mandfeish's Magikarp ability might lead to being mistaken for having Fishman ancestry.
The varied abilities come from the Devil Fruit, and the concept that Fruit Ability Users can't swim is deeply ingrained in the World Government's view.
Arceus's ability to grant others powers will inevitably be exposed over time; it's done openly, like a revelation, to motivate subordinates to work harder.
These people are loyal confidants now, but as the Beasts expand, government spies might approach.
This ability might interest the World Government, but not enough to deploy their entire force, likely just sending some agents for covert actions.
Not everyone will draw Water Type abilities or personal transformations. Mandfeish's luck can't extend to everyone; swimming-capable ability users will always be few.
Moreover, abilities vary in strength, but the user's significance is crucial too. The extent of developing the fruit depends on the user's talent.
To the World Government, only those intending to overthrow the world order are real enemies, like Wald who escaped prison in the original timeline, Zephyr leaving the Navy to become Z, or Rocks kidnapping the Heavenly Celestial Dragons at Divine Valley, and the Revolutionary Army's Dragon.
Kaidou is seen as a powerful pirate but not a true major threat; otherwise, the World Government wouldn't trade with him, selling things like the Numbers to him.
Shanks can even meet the Five Elders directly. Whatever the World Government does secretly, no one can be certain.
Compared to Magikarp's ability, the true identities of King and Shaina becoming public would interest the government more.
Racial identity can be disguised, but granted abilities can't be hidden unless those who receive them become homebodies, never stepping outside.
But in doing so, it negates the purpose of granting abilities, though orders are given to keep their mouths shut outside, only delaying exposure.
However, there's no need to be overly anxious; currently, the frequency of ability users appearing is not unusual.
With the World Government's laissez-faire management style, except for the murder of a Heavenly Celestial Dragon or a member nation's political upheaval, other matters are minor.
The political issues of member nations must surface publicly; otherwise, no one will address them.
Handling threats when they arise is the World Government's attitude on most matters. After all, Lord Imu periodically clears things, the true ruler of the World Government.
...
Power flowed from Arceus into Mandfeish, and this time it didn't take a few days; the effect was immediate. Mandfeish felt the power surge within him.
"Hey! Mandfeish, what are you spacing out about? What did you get after all?"
"Yeah, why so fast this time? Are you unable to do it?"
Seeing him spacing out on stage, those below immediately started heckling; these were people who enjoyed watching the commotion.
"Stop spacing out, what ability is it? Show us now!"
"Shut up! I'll show you my power now!" He said as he began to harness the energy within him, guided by his thoughts.
Red scales began to appear on the surface of his body, two golden whiskers extended from the corners of his mouth, and at first glance, it somewhat resembled Kaidou's transformation stance.
"No way, does this guy have..."
"Something similar to Brother Kaidou... Haha! What's this ability?!"
The pirates below went from shock to stupefaction, then from stupor to laughter. The initial transformation seemed powerful, but as it ended and Magikarp's appearance fully emerged, everything changed.
Indeed, it's Fish-Fish Fruit, but his Fish-Fish Fruit is really a fish.
"What are you laughing at! Do you have this power?!"
"No, we know you got power, but... we can't help but laugh, have you turned into a Fishman? Can you go underwater?"
If he can swim, his spot as a scout would be steady, probably only second to Elizabeth.
"Yes, and that's not all..."
Mandfeish jumped into a nearby fountain, not feeling weak and able to float easily.
Then he felt the more detailed abilities, stronger vitality, and noticed some connection between the previous Splash and his abilities. He felt he could jump higher now; his body became tougher.
With a hard leap in the water, his jumping ability was several times stronger than before, as expected.
He patted the scales on his body, finally drew a small knife from his waist, and stabbed himself. The blade didn't pierce the scale armor but slid off, leaving no marks on the scales.
This could be considered an additional ability.
After all, Magikarp has almost no flesh; apart from the organs, it's all scales and bones. His Human-Beast Form is akin to having scale-bone armor, very tough.