Add CAPTCHA (not using comment_form())

Why are you seeking to add captcha as well as Akismet? It is less reliable. The Recaptcha plugin also makes everything appear as spam so is not recommended.

Does Akismet put its captcha to comments? It’s just I thought it does. If it does I can’t see it on my custom comment form. And if it doesn’t then I’m sorry, it was a misunderstanding ??

No, Akismet doesn’t provide a CAPTCHA