My tigers are sitting on the bottom right next to each other and about every 20 seconds they're tails vibrate up and down for a second. What does this mean? Are they talking to each other?

It's a behavior seen sometimes before spawning, but mine have done it many times and have not yet laid any eggs. Maybe one of them want to breed?

They're both babies though.

normal it could be a sign of breeding but more likely a dominance thing between the two of them

My 2 O's
do the same thing my albino
is sexuly mature but my red O isnt so
its either mating or territorial thing =P

no one really knows why they do this but it is suspected it is a communication thing.

Oscars do this when there is aggression with other oscars and other fish. They also apparently do it when getting ready to breed

x2 on the communication thing.
Mine did it upon introduction of the new tiger into the tank, but still do it, now they're very close and friendly to eachother.