I didn't use any fish to solve it. It can be solved using only "simple" vanilla and NC techniques.

Triple click to read the other hint that I wrote:In my previous hint I deduced:

r8c8 = 8, r4c7 = 9, r9c7 = 5, r7c4 = 9

From there:

{35} @ n789 -> r7c2 = 4 (HS @ r7)

r4c6 = 5 (HS @ n5)

7 @ n2 -> r13c6 <> 6

5 @ n2 locked @ r13c4 -> r2c6 <> 6

5 @ n9 -> r7c6 <> 6

r8c6 = 6 (HS @ c6)

5 @ n8 -> r7c1 = 6

r7c3 = 5

r7c56 = [78] (HS @ r7)

4 @ n8 locked @ r8c4, r9c6 -> r9c6 <> 3

r9c5 = 3 (HS @ n8)

-> r8c7 <> 4 = 7

r9c9 = 4, r8c4 = 4, r9c6 = 1

2 @ n8 -> r7c12 = [12]

6 @ n58 -> r359c2 <> 7

r1c2 = 7 (HS @ c2), r3c9 = 7, r4c8 = 7

7 @ n68 -> r6c2 = 6 (HS @ r6)

7 @ n12, 5 @ n6 -> r3c5 = 6, r2c3 = 6

r6c1 = 5, r3c4 = 5, r2c2 = 5, r1c9 = 5

r1c7 = 6, r5c9 = 6

r4c5 = 4 (HS @ r4)

r4c13 = [32]

...