Why is "fixe" a "cool" thing in Portugal?

Question

Is it because Portuguese people love fish? Or is it because fish are cool? (pun intended)

I read fixe's pronunciation question in here, heard the Google Translate pronunciation and the word resembles fish(uh)... The plural is fixes and I assume it is pronounced as fishesh (google's audio is a little messed up on this).

I also found some attempts of explaining its etymology in here, but the comments suggest that this is an extremely old word (probably as old as the country itself). Here are some quotes:

• The origin of the word fixe is linked to the British tourists visiting the Algarve. [...] The British tourism in Portugal has a long tradition (especially since the beginning of the 20th century) and one of the things that tourists loved was our cuisine, particularly the fish dishes (since "fish and chips" was barely the only fish dish they knew about). Thus tourists in Portuguese restaurants would ask for fish and would savor it with great pleasure and satisfaction. So the word fixe in Portuguese was naturally brought up by this phenomena and it would refer to something cool and great.
• In fact, the actor Vasco Santana pronounces the word fixe in a scene from the movie Canção de Lisboa (1933).
• "A Alma e a Gente", season 5, in an episode about Sintra (#5) after minute 20, Prof. José Hermano Saraiva says that the future King Afonso VI (1643-1683), a sickly child, would say nothing but fixe.

The dictionaries just provide the definition:

• infopedia: an exclamation that expresses pleasure, excitement, satisfaction, joy, greatness, excellency and wonder;
• priberam: something that pleases or have positive qualities.

So what gives? Where does this great fixe comes from? Is it still fresh or is it getting stale already?

Answer 1

The Dicionário da Academia das Ciências de Lisboa (DACL) has two entries for fixe (/ˈfiʃ(ə)/; hear it in Forvo), giving the French fixe (/fiks/) as its origin. Houaiss dictionary (Lisboa, 2003) however just says it is a popular modification of fixo, probably under French influence. I quote DACL, as it has more examples:

Fixe (1) Feminine and masculine adjective. Colloquial.
1 Que não muda; que é seguro; firme, fixo. Estava com medo que a escada não estivesse bem fixe e que ele caísse desamparado.
2 Que é honesto, leal; que é digno de confiança. É um tipo fixe, não vai denunciar seja quem for.
3 Que é simpático, prestável,bom; que tem qualidades que atraem os outros.
4 Que agrada, que dá prazer. Assistimos a uma cena muito fixe. Esta casa é mesmo fixe!
5 Que é compacto, forte.

Fixe (2) interjection, colloquial.
1 Exclamação que exprime entusiasmo alegria. Fixe! Este é cá dos meus! Fixe! O professor não vai dar aula.
2 Usa-se como forma de assentimento, para provar que algo fica combinado, assente.

According to Houaiss, senses 1.3 and 1.4 (‘nice, pleasing’) applies outside Brazil only; and the interjectional senses 2 in Portugal only.

Except for the French influence, which I'm not old enough to confirm personally, this matches my personal experience. Fixe was used where I grew up in the sense 1.1 of firmly fastened, secure. And when I started hearing it in the other senses (which, I now realise, had been in use for quite some time elsewhere) I've always relate it to firmly fastened, secure. There is a sort of logical sequence from 1.1 to 1.4. Someone who does not change and is firm (1.1) is loyal and reliable (1.2), which is good and attractive (1.3), which pleases (1.4). Meaning 1.5 comes directly from 1.1, I'd say. The interjection (2) is perfectly understandle from meanings 1.2 to 1.4.

The fish-origin hypothesis is just an anonymous comment in a blog, and sounds fishy, to put it charitably. And anyway the 1933 Vasco Santana's quote and the humorous weekly Sempre Fixe, published in Lisbon from 1926, do away with it:

Sempre Fixe, Lisboa, 26-5-1926

The other senses of the word occur even earlier:

Mas todo o Mundo está cheio / De que tu não me eras fixe.
—Se eu te não fôra fixe/ Não te andava adorando;/Pela graça dos teus olhos,/Minha alma se anda matando.
(Teófilo Braga, Cantos Populares do Archipelago Açoreano, 1869.)

Agora, decidiu trabalhar na Gruna do Defunto. Apesar do tempo estar "fixe", eu não achei bom, porque neste mês costuma dar uns aguaceiros na serra, e qualquer agüinha do riacho toma a boca da gruna, e foi assim que morreu o primeiro que entrou. (Lindolfo Rocha, Maria Dusá, 1910) (If this sounds like Brazilian Portuguese, it's because it is.)

Vê Vossa Mercê, que fazendo eu tenção fixe de não meter hoje em filosofias, já entrava nelas sem querer! (António da Costa, Cartas do Abade António da Costa, 1744.)

And Portuguese historian José Hermano Saraiva says in this episode of A Alma e a Gente, after minute 20, that the hapless future King Afonso VI (1643-83), as a child, a slow, sickly child, would only say fixe. Sounds like the interjection here.

I didn’t find anyone explaining the probable French influence. A possible reason is that French fixe has had the Portuguese meaning 1.1 (‘unmovable, stable’), which likely was where all other meanings sprung form, since the 1300s (CNRTL).

Answer 2

I got to know a guy from Cape Verde and he said "fixe" all the time. So I asked him what it meant and in Cape Verde it is equal to "legal" ou "muito bom" in Brazilian Portuguese. So if your are in Portugal or Cape Verde you can use it to say that something is cool or awesome, but if you go to Brasil and say that people will look at you weird!