There is already a "fish" shell.
diff -ur bsd-games-2.17.orig/fish/Makefrag bsd-games-2.17/fish/Makefrag
--- bsd-games-2.17.orig/fish/Makefrag	1970-01-01 07:00:01.000000000 +0700
+++ bsd-games-2.17/fish/Makefrag	2020-08-06 19:18:43.204492847 +0700
@@ -31,7 +31,7 @@
 fish_all:	fish/fish fish/fish.instr fish/fish.6

 fish_install:	fish_all
-	$(INSTALL_BINARY) fish/fish $(INSTALL_PREFIX)$(GAMESDIR)/fish
+	$(INSTALL_BINARY) fish/fish $(INSTALL_PREFIX)$(GAMESDIR)/fish-game
	$(HIDE_GAME) fish
	$(INSTALL_DATA) fish/fish.instr $(INSTALL_PREFIX)$(FISH_INSTRFILE)
	$(INSTALL_MANUAL) fish/fish.6
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<div class='path'>path: <a href='/guix/log/?id=1d6d048df9eda22a0544cb034606176c8f8fd5a9'>root</a>/<a href='/guix/log/tests?id=1d6d048df9eda22a0544cb034606176c8f8fd5a9'>tests</a>/<a href='/guix/log/tests/guix-gc.sh?id=1d6d048df9eda22a0544cb034606176c8f8fd5a9'>guix-gc.sh</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/guix-gc.sh?id=1d6d048df9eda22a0544cb034606176c8f8fd5a9&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-21 16:16:38 +0200'>2023-04-21</span></td><td><a href='/guix/commit/tests/guix-gc.sh?id=37dd69b44511dc73eb04bdebe8d82c9a0386338e'>tests: Fix checks for expected failures.</a><span class='msg-avail'>...<span class='msg-tooltip'>Addresses &lt;https://issues.guix.gnu.org/62406&gt;.

With 'set -e', a return status inverted with '!' does not cause the shell to
exit immediately.  Instead use '&amp;&amp; false' to indicate an expected failure.

* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh,
tests/guix-environment-container.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-home.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh, tests/guix-refresh.sh, tests/guix-shell.sh,
tests/guix-style.sh, tests/guix-system.sh: Replace uses of '! ...' with
'... &amp;&amp; false' or `test ! ...` as appropriate.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Eric Bavier</td></tr>