They don’t have to put piranha in the waters.
They’re already there. Just ask Boatswain who has chipped paint on the side of a ship there.
Interesting! The bay would be on the extreme high end of piranha's salinity survival range.
I know a Navy Vet who spent a long tour at Gitmo; I will ask him.
I also know that there's an official recreational diving site in the entrance channel -- but have no info on diving in the Bay..
The entire point is moot, however. There is zero evidence that plans to put prison barges at Gitmo are anything but unsubstantiated internet rumor. For example, the touted big capital outlay for refurbishing a pier for berthing prison barges turned out to be bogus. OHI surveillance of the pier project that required a delay and expense for "diamond-core drilling" of some piers...
...revealed it was not "re-furbed" -- it was totally removed:
And, to date, there has been zero OHI evidence of any big barges anywhere at Gitmo.
TXnMA