Life on Titan would have the property of drinking liquified methane like it's water since life on titan would make use of liquid ethane/methane the same way life on earth uses water.

If a human drank liquid methane, he/she would die a slow horrible death.

Europa's life would live deep under water in a highly pressurized environment and have no need for eyes. 

The latter would justify having a pressurized aquarium placed somewhere, just hope the glass isn't easy to break.