Heat source for my betta

Question
QUESTION: Hi, Lynda. I didn't have much success getting a clear answer to this question with another expert, so I'll give it another shot and be as specific and brief as I can. No matter where I put my beta fish in the house, the water invariably drops below 68 degrees, and so I sought out a heat source. I tried EVERYTHING and finally had success with a clamp lamp and a 75 watt black light above the water which keeps the temperature at exactly 80 degrees. I chose the black light because I keep him in my room and a brighter light would keep me awake at night since I leave it on all the time. My question is this: Does the constant use of the black light keep my fish from "sleeping" at night or fatigue him in any way? My understanding is that the fish can not see this particular color, and hence, he is not bothered. My main goal is to keep the temperature of the water steady at all times (80 degrees being good for a beta) since constant fluctuations are not good for him. But I don't want keeping it on all the time to cause him stress. He seems to be in a resting state at night and more active during daylight hours. (Less active at night, just sort of hiding and hovering in the stalks of his plant.
Thanks for your help.
Tess

ANSWER: Hi Tess,
Bettas do not like lights, and should never be heated with lights. Bettas prefer the light of day.  They must have a thermostat that will keep the water at the same temperature all the time.  Light will cause him stress, and stress fish get sick.  When bringing up the temperature with a thermostat, this must be done very slowly.  One degree every two days, as bringing up the temperature too quickly would be deadly.  
I hope this helps.
Lynda

---------- FOLLOW-UP ----------

QUESTION: Lynda--My beta is in a larger but same shape as shoe box container. I have tried everything and no one seems to be able to tell me how to keep this small amount of water steadily warm at 80 degrees. I'm not sure what you mean by a thermostat, however it isn't possible to raise the thermostat in the house any higher than 68. The only option would be a small ceramic bulb which emits heat but no light. I'm also not sure why a fish expert told me that a beta is not able to see black light.

Answer
Hi,
If you go to a pet store, they will sell you a thermostat that you can put in the water, however you will need at least a 2 gallon tank, and 5 gallons is best.  In their habitat the betta may live in shallow water, but he has lots of room to swim.  There are submersible heaters to keep your water steady, where it will not fluctuate.  Ask your Pet Store Manager to guide you, as there are many different kinds.  You will also need a thermometer to see the temperature of the water.  All experts have their own experience with fish, so an answer may vary.  Having bred bettas, and have had them for a long time, it is my opinion that no fish should be heated with a light.  The reason for this is that the water may be warm at the top, but cooler at the bottom, and this is not good for fish.  This causes different temperatures at different levels, and a fish can get sick.  The water should always be stable at all levels in his water.
Lynda