Aquarium Lockscreen is a port of the popular Aquarium Cydget package. The lockscreen theme has the following features.

[1] Five animated fish swimming in a fish tank(Animated sprites)
[2] Digital LCD clock (12//24 hour clock)
[3] Digital LCD Day and date display
[4] Animated bubble effect in the fish tank.
[5] Settings screen to choose backgrounds, ON/OFF for calendar/day-date widget

This theme requires Winterboard, it will be installed auotmatically. You can enable this theme from the Winterboard configuration panel in your Settings app.

See More Info below for Screenshots