Bonsai ficus leaves turning yellow

[saltyL]

Can you tell by the photo if my bonsai is suffering from some infection or pests or is it "just" underwatering problem.

If it is underwatering can it be saved and how? I have overwatered it now and submerged it in sink filled with water. Can I do anything else?

 

[Silentrunning]

There could be a number of reasons for the yellowing:
Bad or used up soil.
Too wet
Too dry
Too much sun
Plant got cold
Improper fertilizer
Buggs
Fungus

The good news is if your weather is warm you can repot it in fresh bonsai soil and prune it back to green leaves and it should survive.

 

[Chuck]

When was the last time you fertilized it? Your plant shows chlorosis which is normally caused by a lack of nutrition, usually beginning with nitrogen or iron. Give it weekly applications of ficus fertilizer or something like 10-10-10 or any type of organic fertilizer.