Are these fish from different genus’s?

[ILikeFish!]

Are these flame angels from different genus’s because one has really thick black lines with darker blue on the tail and one has very thin black lines with lighter blue on the tail?

 

[Cheese Griller]

Nope, still the same species. Just phenotypic variation within populations.

 

[ISpeakForTheSeas]

As mentioned, they're the same species (and genus), but fish from different places (with different populations) can look a little different.

 

[i cant think]

Are these flame angels from different genus’s because one has really thick black lines with darker blue on the tail and one has very thin black lines with lighter blue on the tail?

Nope!
All Flame angels are from the same genus. I believe you were more intrigued in being different species over being from different genera.
If you want I can go more in-depth in the Genera, Families, Order, Species, Subgenera, Subspecies ect.. however the simple way to explain it is;
A Species is the singular specimen of a genus. A genus is a group of fish with incredibly similar characteristics of a certain thing and a Family is fish with similar but not all the same characteristics just the basic characteristics are often similar if not the same.

This can be complicated when we add in the fact fish can differ upon region of origin as certain populations can be split from eachother and evolve slightly differently (E.g. Go duller to match with the environment or become brighter to stand out in plain sight but still hide).