Oh, one does...it is no longer allowed in that yard and the zoo is looking to move or ship out the pacu.
Interesting idea though, just don't think that the average zoo visitor would want to see half-eaten fish floating in the pool.
There is no need to worry about half-eaten fish floating in the pool...the jaguar took good care of its meals.
When our two black jaguars were younger and used to go in their pool, we would occasionally put live fish in for them to catch as an enrichment. We would get the fish from Arizona Game & Fish from their breeding ponds that they stocked for release for fishermen. I'm not sure what they were (maybe trout or tilapia), but definitely smaller than pacu. The one time I saw it, one of the jaguars would dive underwater, catch one, take it up on the bank and eat it, then go in for the next one. Her sister did not like to go in the water any more (she used to) so just sat on the bank and watched. Now neither one of them goes in the water anymore, so we had to stop doing that, though we still occasionally do it for otter and polar bear.
The zoo are getting smaller fish so they can re-introduce the jaguar back into the exhibit, but need to get someone to take the bigger ones is the harder part