The most common and most likely answer to this crossword clue is the 2 plus 4 letter word ON LINE
I've seen this crossword clue in Financial Times
O
N
L
I
N
E
Buddy explains!
The straight part
We know that "Technically connected/how fish may be caught" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case technically connected/how fish may be caught = on line.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ON LINE mean?
ON LINE adjective- Of a system: connected (generally electrically) to a larger network.
- Available over, or delivered from, the Internet.
- Connected to the Internet.
- Available on a computer system, even if not networked.
- Of a system: active, particularly building facilities (such as power) or a factory or power plant.
- While online; while in a running or active state, or connected to the Internet.