What shrimp can I mix with Bettas?

[Big Bubble00]

So... I told my sister to buy a new tank for her betta fish. She kept the betta in a bowl and it doesn't look very happy.

So I found a 3,7 liters bowl online and told her to but it. I also told her to to buy an Egeria Najas since they are easy to plant. Then I was wondering on how to make the tank clean from the algae and my only idea is... Shrimps. What shrimp can live with betta fish?

 

[Fresh2o]

Really depends on the temperament of the betta. Some can be passive and some can be aggressive when it comes to shrimp. Amano and ghost shrimp, though not colorful, are typically on the larger side.
This is an unfiltered and unheated bowl? This is not an ideal home for the betta, though probably better than its current situation. I would go for more volume before thinking about adding anything to it.
As for dealing with algae, you can control it by limiting or reducing the lighting.