It doesn't learn Bubble. It does, on the other hand, learn BubbleBeam, which it learns at level 25.
It can't learn it whatsoever
Level 25.
You can teach Tentacool the move Waterfall anytime. Waterfall is an HM, not a move gained by reaching a certain level.
It doesn't learn it at a level because it's a tm but it can be teached surf at any level
rattata does not learn bubble at all, there isn't even a TM for bubble
Tentacool will learn Bubblebeam at level 19; Water Pulse at level 33 and Hydro Pump at level 47. You can always teach him the following TM's and HM's: Scald, Rain Dance, Surf, Whirlpool, Dive, Waterfall and Brine.
Tentacool evolves into Tentacruel at level 30.
Tentacool evolves into Tentacruel at level 30.
Tentacool evolves into Tentacruel at level 30.
Tentacool evolves at level 30 into Tentacruel.30
Tentacool evolves into Tentacruel at Level 30.
It doesn`t learn that move in any Pokemon games :(