A fish caught inside the harbor at Fukushima I Nuclear Power Plant was found with 254,000 Bq/kg of radioactive cesium, highest so far.
From independent journalist Ryuichi Kino's tweets, as he watches the live TEPCO press conference:
As to the fish inside the [harbor] at Fukushima I Nuke Plant, TEPCO consulted the fishermen in October [last year] and took measures to stop the fish from escaping the harbor. TEPCO's spokesman Mr. Ono says they didn't do anything about the fish escaping the bay until October. The highest level detected so far in the fish is 254,000 becquerels/kg of radioactive cesium (Cs-134 and Cs-137).
The fish with 250,000 Bq/kg of cesium was a spotbelly rockfish. Kino continues:
It was spotbelly rockfish that was found with the highest level [of radioactive cesium]. If one eats 200 gram of fish, one gets 0.8 millisievert radiation exposure. If one eats 1 kilogram, 4 millisievert. Of course no one eats [this fish, that much], but we should remember that there are fish like that near Fukushima I Nuke Plant. We cannot say for sure that no fish escapes from the harbor.