To me it appears as a freshwater mollusk, something that is totally separate from everything we know to be a Zora today. I cannot see just how the two could be related. Besides there are a number of various separate species that share similar locations. Kokiri and Deku scrubs live in the forest, Gerudo, and Zuna live in the desert, Anouki and Yook live in the icy regions, so why not have another water species that is separate from Zora?
Every time I look at them, I see many more similarities to octoroks than anything else. Only this creature is a little less monsterish and looks a bit more like a real world animal. Possibly some good version apart from all the other various kinds of octos that attack Link any time they get the chance.