Q. Constant watery stools, massive appetite. Eats anything. Never sick. Never lethargic. Always wants to play. 3 yr old GSD bitch. Feeding potato & fish
DAVID ELBEZE, DVM, MRCVS
A. There might be something in her food that she is allergic to. Try a good quality grain free dry food (e.g. Orijen, Accana, Evolve), transition to the new food gradually over a period of 10 days (every day put a little more from the new food and a little less from the old food). Keep her o the food for 2 months to decide if it helps or not.
Alternatively you can use a supplement called "Pro Fiber" in order to harden the stools, but this is not likely to solve the actual problem.
If the diarrhea does not resolve, bring her to your vet in order to run some tests.