If the simplified version of 態 is 态 is why isn't there one for 熊?
態 to 态

态 is a "new" Phono-semantic compound character. 態 sounds tài, so a simple character 太 with the same pronunciation is chosen for the phonetic part. Then it becomes 态.

This character was simplified by the people who lived in places governed by the CCP during 1940s.


  Why not simplify 灬 to 一 for 熊, but for 魚
  
  Answer: 灬 came from 火 (fire) in the seal script. For 灬 under 熊, it has the meaning of fire. But for the character 魚:
  
   
  
  though the bottom is written like 火, it is not really 火. Duan Yucai's Annotation to Shuowen said: 
  
  
    "非从火也 the semantic part is not 火 (fire)"
    
    "象形。魚尾與燕尾相佀。 (this character) is a pictogram character. The fishtail is just like the swallow tail."
  
  
  Thus, when simplifying 魚, they made 灬 (fishtail) as 一; while for 熊, they kept 灬.