The TA-01 number shows that it was made sometime after the late 1970's. It is the number allocated to Los Castillo by the Taxco assay office.
The 27 is the the design or pattern number.
Plateado, means plated, so the silver colored parts are not sterling.
The stone inlay is, most likely, pieces of chrysacola, not sure about the spelling, but the stone is a green similar to malachite and often has blue sections that look a bit like lapis. It was a popular choice of stone on Mexican inlay pieces.
Not absolutely sure, but it looks as if the fish is the pedestal of a bowl. Just judging from the base, it is a very nice example of Los Castillo work.