Shell problem with remote hosts
Drush was designed for use with bash, not fish.  Would it be an option to make your login shell bash for your remote Drush user?

Your other option would be to submit a patch to Drush to fix this problem.  There are two possibilities:


Modify Drush to use env DRUSH_PHP=... in backend invoke.
Modify Drush to not pass --php when --remote-host is set.


Option (1) may be harmful to remote sites where env is not in the PATH, so it may be a dubious proposition.  It might be okay, though; env is probably in the PATH on most systems.

Option (2) seems better.  There is little reason to think that the path to php will be the same on a remote system as it is on the local system, so Drush probably shouldn't be assuming that the php option is relevant for remote aliases, unless it was set in the alias' %path section.

Either of these actions would require a discussion in the Drush issue queue.