Spectra are hidden until 3 seasons of age. You can (in theory) unlock a dragon's exteriors through training/exercise before then, but you cannot actually see the mature spectra until 3 seasons.
Spectra are not the SOLE source of what stats your dragon has- but they are a very large chunk. When making any breeding selections you should always consider Spectra. Because if you breed solely based on stats alone you might be in for some rude surprises.
Also, having a dragon with all their spectra at the "extreme" ends may not always be a good thing, a dragon with incredibly large wings might be cumbersome when doing anything on land, and impossible to to anything in the water.
Each dragon breed has a specific breed type, such as Earth Dragons are always quite large, and Water Dragons always have fins. All Water Dragons can swim, but none can fly. Those little fins just aren't any good for flying. Just like a Star Dragon's big feathered wings will cause them to drown instantly.
However- you can breed for different spectra. If you wanted to try to breed a line of tiny, fast Earth Dragons that can fly, you could do that. Spectra are controlled by DNA, and by slowly and carefully selecting your breeding stock you can create your own special line of dragons with the Spectra you want.
|Wing Type||Wing Size||Body Type||Finlets||Tail||Sheen|
|Delicate Fins||Teeny Tiny||Immense||Perfectly Smooth||Extreme Spade Tip||Tough Old Hide|
|Typical Fins||Itsy Bitsy||Huge||Mostly Smooth||Typical Spade Tip||Very Dull|
|Fin-like||Small||Substantial||Nubbins||Marked Spade Tip||Dull|
|Wing-shaped Fins||Somewhat Small||Large||Bumps||Slight Spade Tip||Like Leather|
|Only Just Membrane||Noticeable||Kind of Chubby||Distinct||Bumpy Tip||Slight Lustre|
|Thick Membrane||Somewhat Proportionate||Somewhat Compact||Distinct Points||Somewhat Barbed||Soft Lustre|
|Fine Membrane||Typical Proportions||Unexpectedly Strong||Compact Points||Barbed||Lustrous|
|Delicate Membrane||Rather Disproportionate||Compact||Crescent-like Points||A Few Barbs||Sparkling Lustre|
|Fragile Membrane||Clearly Disproportionate||Very Compact||Flexible Points||Slightly Tapered||Shine|
|Slightly Tattered||Large||Agile||Soft Points||Tapered||Polished Gleam|
|Fairly Tattered||Quite Large||Sleek||Slightly Tufted||Fine Point||Reflective|
|Typically Tattered||Very Large||Lithe||Fairly Tufted||Some Frills||Slightly Reflective|
|Long Tatters||Expansive||Lissome||Spikey Tufts||Slightly Tasseled||A Little Slick|
|Stiff Tatters||Magnificent||Slender||Slightly Frilly||Tasseled||Slightly Slimy|
|Only Just Feathered||Serpent-like||Somewhat Frilled||Profuse Tassels||Slimy|
|Somewhat Feathered||True Serpent||Frilled||Gross|
|Profuse Feathering||Extremely Frilled|