When I was growing up anime was somewhat of a niche type of content that only few people watched. Before the internet, there weren’t that many places you could get a hold of it and it was typically on Cartoon Network I would get my fix of shows such as Dragon Ball Z and Tenchi Muyo.
Nowadays, anime is so big that it;s a part of mainstream culture, rather than a niche with more and more people looking for a fix; some looking for it on Twitch.
Can you stream anime on Twitch as a streamer
Unless you have a license or have been given explicit permission for the content you are violating the Twitch terms of service and run the real risk of a DMCA strike and potential suspension.
The official wording on this is
Twitch respects the intellectual property of others and follows the requirements set forth in the Digital Millennium Copyright Act (“DMCA”) and other applicable laws. If you are the copyright owner or agent thereof and believe that content posted on the Twitch Services infringes upon your copyright, please submit a notice following our DMCA Guidelines, which include further information about our policies, what to include in your notice, and where to submit your notice.
Twitch terms of service – Respecting Copyright
If you search anime on Twitch, though, you might actually find some channels streaming various anime related shows such as Anime World.

Dig a bit deeper and you find some flimsy interpretation of copyright law which reads

This is false, as the anime is being streamed for entertainment purposes. And then lastly you have this cracker.

And now the excuse is “if everyone else does it it’s fine” which is not correct and could themselves and anyone else believing this excuse as well.
Streaming anime like any other copyrighted and licensed work is not allowed on Twitch and the ones who are streaming it have just not been found yet, it’s as simple as that.
But, there is a way…
Can you stream anime in Watch parties?
There is a way to stream anime through Watch Parties. Streamers would need an Amazon Prime or Prime Video subscription and away you go. However, viewers would also need a Prime subscription to join the watch parties meaning they could have watched it by themselves anyway.
Therefore, if the question is can you watch anime on Twitch for FREE then the answer is no.
What if you watched pirated anime on Twitch?
Twitch do not seem to clamp down on the viewers who watch OTHERS stream anime on Twitch, but it doesn’t make it illegal. Ignorance of the law excuses no one. However, viewers watching pirated content have not broken the same laws as the ones streaming it – no action is likely to be taken against you but it is not impossible.
Closing comments
It is fairly obvious what can and can’t be streamed on Twitch – anime is not in a special category away from movies, tv shows and so on. Although it is possible to stream anime, it is not free and such hard work that it’s not worth bothering with.
The risks of streaming it are so high and the reward so low we’re not sure why people bother.