You could raise them if you want but at some point you may have more than you want. You could always sell them on the forum or to your local store if they will buy them.
I thought there was a great article on how to raise them on TPT but I can't find it.
Eheim Pimpette #270
Eheim Pro II 2028; Classics Series -2215, 2217, 2260, 2262; Pro 2229 Wet/Dry