魚

substitute fish; using an alternative fish variety instead of a traditional one

saltwater fish

pipefish (esp. the seaweed pipefish, Syngnathus schlegeli)

barracuda (Sphyraena spp.)

Indo-Pacific blue marlin (Makaira mazara)

silverfish (Lepisma saccharina)

Proverb

kindness begets kindness; you scratch my back and I'll scratch yours; if the water is kind to the fish, the fish will be kind to the water

Sensitive

frogfish (any fish of family Antennariidae, esp. the striated frogfish, Antennarius striatus)

Ischikauia steenackeri (species of cyprinid fish)

Idiomatic expression; From Mencius

to be unable to accomplish something because one has chosen the wrong method; to ask for the impossible; to look for fish by climbing a tree

Word usually written using kana alone

large-headed midnight fish (Poromitra crassiceps)

armored fish; armoured fish

Idiomatic expression

person who just tags along; hanger-on; person who follows someone around like a shadow; clingy person; goldfish poop

wahoo (Acanthocybium solandri)

Encheliophis sagamianus (species of pearlfish)

fish large enough to swallow a whole boat; colossal fish

Idiomatic expression

great man; notorious man

cleaner fish

redlip mullet (Chelon haematocheilus)

artificial fish reef

black carp (Mylopharyngodon piceus)

salt-cured fish

Japanese clawed salamander (Onychodactylus japonicus)

cuttlefish; squid

Bering wolffish (Anarhichas orientalis)

biwa trout (Oncorhynchus masou rhodurus); biwa salmon