I'd get around 7 cherry shrimp, unless you can pick and choose which shrimp you will be buying. if you get to pick, and if the shrimp offered are adults, you can easily just snag 2 males and 2 females and be set for breeding them. but otherwise 7 small juvies should give you a decent chance of getting what you need. yes this jar looks really nice and full now, and as long as the plants are healthy and growing, its definitely ready for shrimp. you will want around 5-7 adult shrimp in here max.