Can you take the train there and if so how close will you be

Yes there's a stop specifically for the aquarium and it's about a 2 min walk .

Yes the blue line takes you right there it is the aquarium stop

The MBTA (the T) goes right to it. The blue line goes right there, and the green and orange line are not too far away.

There is a stop on the t for the aquarium

blue line aquarium station is just close to this