betta fish light in tank

Question
How long is too long to keep a light in the tank of a betta fish? I usually keep it on during the day and turn it off at night. Is this a good idea considering its a tropical fish or maybe turn it on for only short periods of time? Also I noticed a small white dot on the fin of my beloved betta is this bad, he seems happy?

Answer
Hi,
Tropical fish don't actually need light to survive, they will be perfectly happy in the darkness, but we usually have lights in our tanks for 2 reasons:
1) So we can actually see our fish easily.
2) Plants need light, so if your tank has live plants, keep the light on for around 9-10 hours a day, but if it's on for too long, you may get algae growth.

The white dot may be white-spot. They are usually tiny flecks of white that start off on the fins, and spread. If it looks like white-spot, raise the tank temperature to 29 degrees Celsius, and buy a white-spot treatment from your local fish shop.
If you're not sure what it is, please take a picture/s and upload it to photobucket.com. Then send me the link. I'll try to identify it and tell you what to do.

Best wishes,
Kathryn