Falsche fish is literally false fish (gefilte style), made from chicken meatballs prepared and cooked as if they were gefilte fish. Grated onions, carrots, salt and pepper are mixed with ground chicken, and the balls are dropped into boiling water prepared exactly as you would for your gefilte fish. I have made this occasionally (not for Pesach, per se, because I eat fish on Pesach), and it really is delicious, and truly VERY close to gefilte fish when served cold (and with chrein).