the lower panel komarisa is kinda funny, from a perspective it looks like it's tongue is out, but from another it's just screaming while her tongue is inside it's mouth.
Reminds me of an uncle who kept a piranna. He fed it guppies (small fishes). Most of the time it just took a bite out of one and didn't eat it, apparently out of idle boredom.
i know it may be mean, but i would pur a marisa in with the nitori and tell the nitori that they would be fed to a flan if the marisa ever went missing or somehow wond up dead. oh and just to screw with them more i would feed the nitori baby marisa and make the marisa watch while still treating the marisa as a pet
But then, it could be a fun feeding Nitori with food-grade koyukkuri, watching how they predate.There will be an interesting scene if you insist on putting Nitori together with the other two...