I'm not exactly sure what you are asking. It seems that the Christmas tree lights are reflecting in the glass on the front of the tank. It looks to be about a 20 gallon. It might be ok for a smaller water turtle. It's a nice-looking aquarium. Are you thinking of buying it?
Looks bigger the. 20 probably 50 gallon. 20 gallon are 30 inches 40s are 36 inches long. With the weird front tho it can be like either a 37 gallon, or depending how wide it can be like 44 gallon, but it's right around that 40gal mark