some may interbreed and others won't. forr example yellow neon and red cherry shrimp(both neocaridina heteropoda sp) are part of the same species/ genus, so they will interbreed. but if you put tiger shrimp(caridina sp) with the neo caridina species they wont interbreed. and some shrimps of the same species wont interbreed with the same species beacause they are different genus. so when you buy different shrimp for one tank remember to check the species of the shrimp. if the same they wil likely interbreed so you shouldnt put them together, but if it is different then they wont interbreed so you can put them together.