Gakuen Sensuikan-tai: Mermaid Girls - Vol. 1 Ch. 1 - World of Mermaids

[MangaDex]

 

[PechWild]

Male invaders: monstrous marine-creatures-lookalike.

Female invaders: hot monster girls.

Classic sexualized sexual dimorphism.

 

[Kushikime]

Succubus and Hitman creator duo? I’m locked in. Thanks for the chapter !

 

[Flame-2-Haze]

Basically: Underwater Strike Witches, with a dash of gores on the side.

EDIT: Or a variety of Sky Girls if you go a little further back.

 

[mrboxeater]

Looks like dumb fun but i cant get over the ugly ass guns ffs. thanks for the TL

 

[Faztri]

Cute girl action with gore? Yup, MaGi Spec-Ops Asuka creators

 

[genderbenderbb2]

Monthly updates for this one~.

 

[Zoshlog]

The authors of "Magical Girl Spec-Ops Asuka" reunites!*

I thought it was a sequel at first