I have a 20 gallon long tank exclusively for red cherry shrimp. These are some very hardy shrimp. I don't test or condition my water and they do just fine. They're way more active in warmer water (around 78-80 degrees F). I started this tank about 3 months with 15 shrimp and now I have 40-50 shrimp total. All of the shrimp were under 3/4" when I got them and now some of them are about an inch. As with most aquatic life, consistency is key. If you keep their water consistently warm and clean, your shrimp will breed prolifically. As to using them for fish food, I've never tried it. I'm growing them up to put in my other tanks to clean algae.