This is male PDERT (Platinum Dumbo Ear Red Tail) guppy named "Pauli".
(sorry for the blurry image, Pauli can't sit still!)
Eponymous to (aka named after or "namesake") Wofgang Pauli, the famous physicist that explained why our hands do not "go through" what we perceive as "solid objects" and can actually hold, push or pull things in the macro world.
Hint: Contrary to popular belief, it has nothing to do with positive or negative attraction.
Wolfgang Ernst Pauli (/ˈpɔːli/;[6] German: [ˈvɔlfɡaŋ ˈpaʊli]; 25 April 1900 – 15 December 1958) was an Austrian theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics for his "decisive contribution through his discovery of a new law of Nature, the exclusion principle or Pauli principle".
The discovery involved spin theory, which is the basis of a theory of the structure of matter.
(https://en.wikipedia.org/wiki/Wolfgang_Pauli)
Submitted FYI.
May you and yours be well and loving life today.
In Lak'ech,
Jaichai