Summary

these creatures are called silverswimmers which will replace the fish that were wiped out during a mass extinction

and their ancestor are larval crustaceans

but I can only 2 species of silverswimmer you just seen

the other species I tried doesn't work on my program for them but again only 2 have made it for 3D Printing

https://www.youtube.com/watch?v=kedHEfbeAzU