Also, I don't know who told you the 5 ice cubes routine, but it is a terrible way to water:
1) when you water your tree, you should always water thoroughly so that all the soil has been moistened. Put it in the sink, pour water in it until the water is running freely out the drain holes. Let it drain and then do it again. "for bonsai, it always rains twice."
2) Never water bonsai on a schedule. Water it when it needs it. That will be different amounts of time depending on season, how actively it is growing, ambient temperatures, etc etc. Read about the chopstick method to tell when it needs it:
https://www.helpfulgardener.com/forum/vi ... od#p387765
Right now, with no leaves, your tree will be using very little water.
Offhand the five ice cubes a week doesn't sound like enough water for when it was growing, but that depends on how moisture-holding your soil is, etc