Fenix sits next to 3 phonetic neighbors — Phoenix, Phineas, and Felix are the closest matches by sound. Most share Fenix's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"dark red, crimson"
"son of the grey-haired one"
"noble and peaceful"
"of the field, strong"
"magical, sacred water"
"kingly, held by the heel (supplanter)"
"passionate, ardent"
"son of Thomas, son of the twin"
"anglicization of Welsh Llwyd"
"eighth-born"
"boar-friend, warrior companion"
"God is gracious (related to Yohanan)"
"holy name, name of God"
"gift of Yahweh"
"the fifth"
"calm, tranquility"
"modern invented name with noble, airy connotations"
"handsome one, bright fire"
"generous, tolerant"
"son of Jet, swift one"
"creative expansion of Mazie (pearl) + -on suffix"
Similar sound: These names share phonetic patterns with Fenix — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Fenix.
Rhythm: Fenix is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.