Masa (feat. GUMI) - Himitsu no Kingyo

[EJTranslations]

I don't listen to much Vocaloid stuff these days, but I came across this song, and then I came across several not-very-good translations of it (none of them even got the title right!) and was motivated to do a more accurate one. So here I am, making sure it is in fact accurate. There's only one place where I'm really confused, but of course I'll take any feedback you've got.

見せて隠して
秘密の金魚
知らないよと
孤独のつがい

misete kakushite
himitsu no kingyo
shiranai yo to
kodoku no tsugai

Show it, hide it
The secret goldfish
"I don't know," says
The mate of loneliness [1]

私が隠した秘密を
見せても構わないよ
だって私たちは
「友達ナンダカラサ」

watashi ga kakushita himitsu o
misete mo kamawanai yo
datte watashi-tachi wa
"tomodachi na n'dakara sa"

I don't mind showing you
The secret I've hidden
"Because we're
Friends, aren't we?"

目玉，耳，口
髪ノ毛マデ
全テガ
愛シスギテ
二人ダケノ
秘密
「友達ナンダカラサ」

medama, mimi, kuchi
kami no ke made
subete ga
itoshisugite
futari dake no
himitsu
"tomodachi na n'dakara sa"

Eyeballs, ears, mouths
Even the hairs on the head
I love them all
Too much
It's a secret
Just between the two of us
"Because we're friends, aren't we?"

触れて隠して
秘密の金魚
あなただけが
孤独のつがい

furete kakushite
himitsu no kingyo
anata dake ga
kodoku no tsugai

Touch it, hide it
The secret goldfish
You alone are
The mate of loneliness

見セテ隠シテ
秘密ノ金魚
知ラナイヨト
孤独ノツガイ

misete kakushite
himitsu no kingyo
shiranai yo to
kodoku no tsugai

Show it, hide it
The secret goldfish
"I don't know," says
The mate of loneliness

私の秘密は
この箱に
誰も知らない
君の箱

watashi no himitsu wa
kono hako ni
dare mo shiranai
kimi no hako

My secret is
In this box
No one knows about
Your box

肋骨(あばら)，鼻，指
足首マデ
全テヲ
集メタクテ
ワタシダケノ
秘密
「友達ナンダカラサ」

abara, hana, yubi
ashikubi made
subete o
atsumetakute
watashi dake no
himitsu
"tomodachi nan dakara sa"

Ribs, noses, fingers
Even ankles
I want to
Collect them all
It's my
Secret
"Because we're friends, aren't we?"

見せて焦らして
秘密の金魚
わたしだけに
教えた秘密

misete jirashite
himitsu no kingyo
watashi dake ni
oshieta himitsu

Show it, tease it
The secret goldfish
A secret told
Only to me

見セテ隠シテ
秘密ノ金魚
嬉シイヨト
貴女(あなた)ヲ包ム

misete kakushite
himitsu no kingyo
ureshii yo to
anata o tsutsumu

Show it, hide it
The secret goldfish
"I'm so happy," I say
As I wrap you up

貴女(あなた)ノ一部ト
コノ子一部ト
アノ子一部デ
トモダチ

anata no ichibu to
kono ko no ichibu to
ano ko no ichibu de
tomodachi

With one piece of you
And one piece of this girl
And one piece of that girl
I'll make a friend

君の笑顔と
秘密の金魚
身体が熱くなって
溶ける

kimi no egao to
himitsu no kingyo
karada ga atsuku natte
tokeru

Your smile and
The secret goldfish
My body becomes hot
And melts

君ト最後ノ
秘密ノ金魚
二人ダケノ
箱ガ閉じゆく

kimi to saigo no
himitsu no kingyo
futari dake no
hako ga tojiyuku

With you, the last
Secret goldfish
The box that belongs to just us two
Is closing

[1] I just don't... really get what the last two lines of this stanza are talking about at all. Grammatically it's not that weird, but what does it mean? "孤独ノツガイ" especially--maybe it should be "the lonely mate"? (Or "the lonely pair," but later it says "あなただけが 孤独のつがい" and one person can't be a pair, so...). I just feel like I'm missing something here.

I'll also take any suggestions for improved wording. I know this gets pretty choppy in places.

[Grain]

When I see that confusing stanza, it makes me think about what tsugai ni naru means. It basically means to "couple up." Following that, what would tsugai ni naranai mean? So to me, calling somebody a kodoku no tsugai sounds like saying they are a lonely bachelor, bachelorette, or a failed lover. If you don't like your current translation, I would make it "lonesome lover."

shiranai yo to
kodoku no tsugai

"I don't know!"
Says the lonesome lover

Anata dake ga
Kodoku no tsurai

You alone are
The lonesome lover

Or maybe you could make it the companionless companion, the solitary companion, the love-lost lover, the lonely bachelor. Whatever the thesaurus allows.

[EJTranslations]

Thank you! That's helpful.