Typical yukkuri dying by existing

woah that's a lot ??

but seems weird since marisa type dissolve easy under water O.O ?

Yeah, seems like a silly cross between two things:

#1. Yukkuri dissolve in water; even aquatic Marisa.
#2. Yukkuri don't breathe, so...

This looks like that thing where Aquatic Marisas don't drown, but because they think they might, they actually die from shock. I saw something like this on a picture where a yukkuri thought it was drowning in OJ/liquor even though they don't breathe.

Have to change the water regularly due to all the dead yus must run up the bill.

Aquatic types sometimes are more durable in water (depending on the author), but the whole Power of Belief probably lets them drown instead of just realize they're still in one piece.

Aquatic Marisa evolved to have better resistance to water and moulds, so they can survive living on water.
But this is strictly like "water resistant" watch (splash proof), not "water proof" (stay ticking underwater).

Their skin don't melt as easily, and seems like they don't emit death stench (or the water just lock the smell inside).

But they still can't swim, so they'll die.
And aquatic Marisa falls to the water too easily.

The water resistance might answer one problem, how they can survive rain without any shelter. I assume rain water is not enough to dissolve their body. Although the wind will still bring innumerable casualty of Marisa fallen overboard.

Maybe they could stay afloat by puffing (too smart for yukkuri).