fiŝkapti

English turns the noun into a verb and thinks nothing of it: you fish for fish. Esperanto cannot do that, because fiŝi would have to mean something vague like "to do fish", and the language does not like vague. So it names the action instead - fiŝ-kapti, fish-catching - and the meaning is exact from the first time you see it.

The head is on the right, as always in compound words: the thing you are doing is kapti, catching, and fiŝ- says what. Change the first root and you change the prey, which is how birdokapti and balenkapti work too.

Then the suffixes do their usual multiplication, and this root is one of the neatest demonstrations of it in the language:

Four words for the price of one root and four suffixes you already know. That is the whole argument for the affix system, compressed into a single afternoon by the water.