Excessive basking is a possible worrisome sign, but there are several possible causes. First, it could be intimidated by the larger tutle, although Paints are not known for agrssiveness. If it had a respiratory illness, it Could be treated, but one has to have an exact weight of the turtle and predilute most of the antibiotics to ensure exact dosage. With a small hatchling, one has to suspect one of several vitamin or mineral nutritional deficiency problems that a growing turtle is prone to. A good commercial diet, such as Reptomin may help, but it is often difficult to start them out is they are already off their food a bit. I personally have had very poor results with juvenile paints compared to some other species.