The Blue Planet Collection

There are five dragons in the Blue Planet Collection:   
Nenufar Dragon    
Waterfall Dragon
Coral Dragon
Penguin Dragon
Lantern Fish Dragon
All are Generation II, and the hardest part of collecting this is waiting to level 22 to get the Dark dragon and after that the Penguin Dragon.

Penguin and Lantern Fish Dragons are the only dragons that don't look like Dragons. Penguin Dragon is the only Dragon in the collection that has no Sea element.
(Double Ice Dragon plays with penguins and eats one of them...)

Nenufar Dragon = Sea + Nature
Breeding 6 hours
Hatching 6 hours

Waterfall Dragon = Sea + Terra
Breeding 4 hours
Hatching 4 hours

Coral Dragon = Sea + Nature
Breeding 12 hours
Hatching 12 hours

Penguin Dragon = Ice + Dark
Breeding 15 hours
Hatching 15 hours

Lantern Fish Dragon = Sea + Electric
Breeding 10 hours
Hatching 10 hours