[Nicecook]

• How often should I be doing water changes in this tank? - I do 40-50 % water change weekly
• How much of the water should be being changed at a time?
• When adding de-chlorinator back in during the water change, do you only use enough for the amount of water you are adding back, or enough for the entire water of the tank? Just for the amount you adding back.
• Am I overstocking, or can I add a few more things to the tank? It's only 15 gallons, I will add a few more but would not go crazy.

Watch for the ammonia levels, you can control this by doing weekly water changes along with nitrates, I would do one right now so there is no ammonia otherwise fish will suffer. Also watch out for algae since you are running the light for 12 hrs.

Good luck!!