+1 to not using live fish.
I wouldn't purée the shrimp. At some point you will want to allow the ammonia levels to drop. Leave it whole. When your nitrites and nitrates are high you can scoop it out. If you want it to work faster, toss in another shrimp. You'll have a heck of a time trying to scoop purée out when you're ready to let the ammonia drop so you can add livestock.
I disagree, though I think you may be missing my point.
The point of pureeing is to allow for a more even distribution of the... puree.
On top of what wooden_reefer stated, leaving a dead shrimp in one place also tend to confine a lot of chemicals to relatively the same spot. Pureeing it, or finely chopping it, or essentially making it small bits allows for the pump to spread it absolutely everywhere.
Ammonia later on can be reduced with a big water change. Or two. Or more.
Since it's tiny, tiny, tiny bits as well, it'll break down much faster and so generate ammonia much faster. There'll be a huge spike, but when you need to lower it, you don't have to take out the puree, because by then well, it's not producing ammonia anymore. XD
Or shouldn't be anyways.
The added benefit is that this is being used by the microbes themselves to reproduce. So you get a bigger population, faster as well.
Bacteria reproduce well, once or so every 20 minutes. So if they have ample food, they'll be able to multiply rapidly. But with just ammonia, it won't work.
They're just like us. Oxygen for example, is very important to us, but oxygen enough doesn't allow us to develop and reproduce. We need well, other chemicals.
Same with bacteria, they need ammonia, and more. Of course, as the whole shrimp decays, some of it does spread elsewhere, but no where near as fast as well, just using puree.
