中辞典 has 鰾膠/にべ as the fish.

gg5, daij

GG5 and daijr/s have a second sense.
Given that there's no kanji overlap in most of the refs, I think it's best to keep the entries separate.

@@ -26,0 +27,10 @@
+<sense>
+<pos>&n;</pos>
+<xref type="see" seq="1571050">にべもない</xref>
+<misc>&uk;</misc>
+<s_inf>usu. as 〜もない or 〜もなく</s_inf>
+<gloss>amiability</gloss>
+<gloss>friendliness</gloss>
+<gloss>graciousness</gloss>
+<gloss>flattery</gloss>
+</sense>

GG5: ニベ  〔ニベから得るにかわ〕 isinglass; fish glue.

GG5 and several EJs have this as kana-only.  We currently have 鮸/にべ as an entry for the croaker fish, and 中辞典 has the 鰾膠 for that entry too.
Given the kanji form and reading overlap, this probably needs to be merged with 2191590. All rather messy.

@@ -22,0 +23 @@
+<misc>&uk;</misc>
@@ -23,0 +25 @@
+<gloss>isinglass</gloss>

鰾膠 and 鮸膠 are in meikyo, obunsha, daijs, etc. with this meaning.

Shinmeikai has this meaning for 鮸, as well as a sense for the fish specifically (our entry 2191590)

I only see 膠 with this reading in jitsuyou in the expression 膠も無い

Google N-gram Corpus Counts
╭─ーー─┬─────────╮
│ 鰾膠 │     183 │
│ 鮸膠 │       0 │
│ 鮸　 │       0 │
│ 膠　 │ 240,033 │
╰─ーー─┴─────────╯