池には魚がたくさんいる。

pond

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

fish

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

a lot; lots; plenty; many; a large number; much; a great deal; a good deal; enough; sufficient; enough; too many; too much

to need; to want