Yes, of course it's a fish, but which one? Vox says: Pez marino acantopterigio, de aletas pectorales tan desarrolladas, que le permiten saltar fuera del agua.

and found this:
milano. m. Ave diurna, rapaz, que se alimenta de pequeños roedores, insectos y carroña. Azor, ave. Pez marino, teleósteo, de los acantopterigios. Vilano
http://www.educar.org/diccionario/m.asp

In other words, it's an acanthopterygian

2 definitions found

From Webster's Revised Unabridged Dictionary (1913) [web1913]:

Acanthopterygian \Ac`an*thop`ter*yg"i*an\, a. (Zo["o]l.)
Belonging to the order of fishes having spinose fins, as the
perch. -- n. A spiny-finned fish.

From WordNet r 1.6 [wn]:

acanthopterygian
n : a teleost fish with fins that are supported by sharp
inflexible rays [syn: {spiny-finned fish}] [ant: {soft-finned
fish}]

acanthopterygian (noun) -
1. a teleost fish with fins that are supported by sharp inflexible rays
Synonyms: spiny-finned fish
http://define.ansme.com/words/a/acanthopterygian.html

It must, of course, have a more specific name, but I offer this info in case it helps you or someone else find it (but I can't find the scientific name for milano, which puts a big spanner in the works)




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Note added at 1 hr 36 mins (2003-11-02 13:34:12 GMT)
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spiny-finned fish
Encyclopædia Britannica Article

also called Spiny-rayed Fish, any member of the superorder Acanthopterygii, including four orders of marine and freshwater fishes having fins with some spiny (as opposed to soft) rays— Atheriniformes, Beryciformes, Zeiformes, and Lampridiformes.

The atheriniform (q.v.) is the best known of the spiny-finned group, including flying fishes, guppies, mollies, swordtails, and California grunion. Beryciforms…
http://www.britannica.com/eb/article?eu=70945