feeding shrimp

Hello all! I'm facing a crisis that is keeping me up at night! For context, I have 2 Clownfish, 1 Royal Gramma, and 1 Cleaner shrimp in a 20L tank. No corals (long story) The city I live in has faced a snow/ice storm that I don't ever remember happening here (Lived here for 22 years). And of...