Sqlite ordering a numeric column startinng by 1 for each category

I have a table called groups ( i fill with this data a treeview )

id type description orden description
-- ---- ----------- ----- -----------
1  1    Aninals     1     Elefant
2  1    Animals     2     Tiger 
......
25 1    Animals     25    Horse 
26 2    Fish        1     Jaws 
27 2    Fish        2     
....

Deleting, inserting, i have jumps in the column orden.
1  1    Aninals     1     Elefant
2  1    Animals     3     Tiger 
......
25 1    Animals     27    Horse 


I need do somehing like this:

//animals
Update grupos set orden = (counter ascendent starting by 1) where type = 1 order by orden
//fish
Update grupos set orden = (counter ascendent starting by 1) where type = 2 order by orden
...

to get the column orden without number jumps.

Can some one help with this sql statement ?