Getting bad speed wobble/fishtailing in left skate

[waterboy1190 0]

So whenever I'm gliding at speed my left skate is wobbling all over the place. Sometimes it's been so bad that it has actually caused me to fall. When it gets like that, I push down with my hands  into my left thigh to lock the skate on the ice. Obviously I can't be doing this whilst playing a game. 

My skates fit well, the blade and runner are fine, my skates are not tied loose, I just can't seem to figure out the problem. I have had it occasionally in my right skate by 99% it's in the left. I just can't solve the problem and it's really bugging me. 

 

Any help would be much appreciated.