Not sure if the blue im seeing is your light but your plant looks pretty healthy but very small. In my experience that would be not proper watering.
Have a spill tray under all your pots and water till you get some coming out the bottom. If your not doing that your plant will be small and you could get some toxicity issues.
I was always scared to water for fear of overwatering.
Remember this one thing overwatering is not an issue of volume, but frequency. Water the shit out of it every 2 days or so. I personally water every 2 days in 5 gallon pots. Hope i helped.