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
530ef8a01f1f4207cb1df235d6da007ca'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=3ae9922530ef8a01f1f4207cb1df235d6da007ca'>refs</a><a class='active' href='/guix/log/HACKING'>log</a><a href='/guix/tree/HACKING?id=3ae9922530ef8a01f1f4207cb1df235d6da007ca'>tree</a><a href='/guix/commit/HACKING?id=3ae9922530ef8a01f1f4207cb1df235d6da007ca'>commit</a><a href='/guix/diff/HACKING?id=3ae9922530ef8a01f1f4207cb1df235d6da007ca'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/HACKING'>
<input type='hidden' name='id' value='3ae9922530ef8a01f1f4207cb1df235d6da007ca'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=3ae9922530ef8a01f1f4207cb1df235d6da007ca'>root</a>/<a href='/guix/log/HACKING?id=3ae9922530ef8a01f1f4207cb1df235d6da007ca'>HACKING</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/HACKING?id=3ae9922530ef8a01f1f4207cb1df235d6da007ca&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-10-23 12:57:20 -0400'>2020-10-23</span></td><td><a href='/guix/commit/HACKING?id=73faee9fb25465f1b236f5f94e1052145655736f'>doc: Fix typo in HACKING.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Contributing): s/informations/information/.
</span></span></td><td>Maxim Cournoyer</td></tr>