Application.start :error 'no such file or directory'

I am running two applications: GoFish.PhoenixApplication and GoFish.GameApplication In one of the controllers of the phoenix application, I want to start the Game like this: Application.start(GoFish.GameApplication)
but it doesn’t start it.
I then tried in IEX but got this error:

iex(9)> Application.start(GoFish.GameApplication)
{:error, {'no such file or directory', 'Elixir.GoFish.GameApplication.app'}}

Then I tried compiling the code again to make sure it was there:

 c("lib/go_fish/game_application.ex")     
warning: redefining module GoFish.GameApplication (current version defined in memory)
  lib/go_fish/game_application.ex:1

[GoFish.GameApplication]

But the error is still the same:

iex(12)> Application.start(GoFish.GameApplication)
{:error, {'no such file or directory', 'Elixir.GoFish.GameApplication.app'}}

I suspect it has something to do with the Elixir Prefix in Elixir.GoFish.GameApplication.app but I’m not sure.

The runtime uses the word “application” to mean a very specific thing - the file with the .app extension will be generated by the Elixir compiler if things are configured correctly.

Starting applications is also usually handled automatically by mix etc; calling Application.start in a controller seems strange.

Can you post some code from, say, GoFish.GameApplication?