I thought I'd like to share what I've learnt. Oh and also, yes, I did get my puppy. The seller (not a breeder, but a army/ coast guard breeder, vietnamese, making some money on the side breeding their working-lines) said it was purebred, but I'm pretty sure he's a hybrid of some sort of alligator, rat and finally, some GSD somewhere in there.
Anyways, I've been reading and found that the problem with fish is that many species contain Thiaminase, a substance which breaks apart Vitamin B1 (or was that B11?), which will cause "malnutrition"... a very bad kind of malnutrition.
I've experimented with a couple of fish and he loves Catfish (Mekong Delta) (he loves the innards as well), and especially Capelin. He slurps up the Capelin like it was Spaghetti! He also hates some kind of fish and would just gnaw on them but not eat them.
Sadly, I found out that Capelin contains high amounts of Thiaminase, so I'm gonna cut it off of our food chain completely starting immediately.
On a brighter note however, I found out through research that Tilapia (and numerous other species: Thiaminase - The Free Freshwater and Saltwater Aquarium Encyclopedia Anyone Can Edit - The Aquarium Wiki
) contain ZERO Thiaminase, and I assume are probably just as good as any other source of meat.
Pacu is the cheapest fish around here but I can't find any information on it wrt Thiaminase unfortunately. (Ironically, I find its the best tasting fish versus all the other way-more-expensive fish.)
So anyways, as its a puppy, and an uneducated first-time owner of a a GSD, or any dog for that matter...
For breakfast I feed it two fistfuls of Pedigree puppy kibbles in warm milk ( Pedigree Puppy Complete Nutrition Puppy Food at PETCO
) with all those added vitamins (yeah I know it's not the best choice by a LONG shot... corn, wheat, byproducts, etc, but I want the vitamins),
For lunch I (fed him about 200gms of Capelin) plan to feed him 200-400g of whole Red Tilapia.
For dinner I feed him a whole chicken drumstick PLUS one drumstick BONE (hey I love drumsticks as well lol).
All raw (except for the kibbles obviously) and fridge (not freezer) temperature.
Poop looks okay.... it's not what I would call rock-solid... but its not runny at all. And it varies from dark brown to lighter brown.
Energy is good and growth, well, I can see this little monster growing, yes.
I still wanna know if I can do mainly fish (tilapia/ pacu) for the long run cuz of the Omega3/6/9 contents... I'm kinda lazy that way, plus I live in a part of Vietnam which has VERY VERY little in terms of variety or products like supplements etc.
But yeah, stay away from Thiaminase-laden fish, everyone! Cheers!