Crossword Clue:

a freshwater protozoan

AnswerCrossword Clue
AMOEBAA protozoan
DACEA freshwater fish
DACEA small, freshwater fish
PIKESPEEKGlimpse from a certain freshwater fish?
DAPHNIAFreshwater crustacean called a water flea
MARINEPertaining to a sea or ocean, but not a freshwater lake