 If you liked
Seto no Hanayome
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 ...then you might like
Asobi ni Iku yo!
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Although the two are about two entirely different things, Nyan Koi! about cats, and Seto no Hanayome about mermaids. However, both have similar genres like they're both romance-comedies and harems. Also both involve the main character getting into some sort of life threatening danger.