EA Oceania - Knight of the deep too good?

[PyroStock]

Both EA Oceania & Rlyeh have national amphibians to hire in mass to access land & conquer indys, like an island, even early in the game. Most land nations require gems and research just to get into the water, even a small lake, unless they happen to get lucky with indy provinces.

An Amulet of the Fish is twice as many gems as a Ring of Waterbreathing, so using that scale a barrel of water would cost 25W + 25A gems, but at that difficulty even a 65W might be preferred.

I haven't dove into the sea nations yet, but do aquatics with the amulet of fish get the same penalties on land that non-aquatics get in water?