What do Japanese fighting fishes eat?

Freshwater fish

lake trout - masu

rainbow trout - nijimasu

river trout - ayu

koi - carp

unagi - eel

Saltwater fish, blue

tuna - maguro

pink, fat belly tuna - toro maguro

sWordfish - kajiki maguro

yellowtail - buri

bonito - katsuo

pacific mackerel - saba

horse mackerel - aji

pike, saury - sanma

salmon - sake, shake

sardine, anchovy - iwashi

herring - nishin

shark - same

conger eel - anago

pike conger - hamo

flying fish -tobiuo

whale - kujira

Saltwater fish, white

blowfish - fugu

flounder, halibut - hirame

sole - karei

cod - tara

sea bass - suzuki

sea bream, red snapper - tai

Shellfish and mollusks

oyster - kaki

clam - hamaguri

baby clam - asari

scallop - hotate

crab - kani

shrimp, prawn - ebi

lobster, crayfish/crawfish/crawdad - Ise ebi

abalone - awabi

conch, whelk - sazae

squid - ika

octopus - tako

urchin - uni

Roe

urchin roe - uni

salmon roe - ikura

herring roe - kazunoko

cod roe - tarako

Hope this was helpful :)