Hi, I'm new in this forum and I tried to search a little for other topics with a similar problem but I didn't got anything with the same description.
My turtle, Leonardo (RES, Trachemys scripta elegans), have been making noises with his mouth when he is in his basking zone. I'm concerned because I never heard him making this before (is like a croaking). At the same time he make a movement with his head, which appears like a biting motion to his right leg, he looks uncomfortable with it (moving backwards). His yawn is normal (he doesn't overdo them) and he doesn't show any other symptom (all his other behaviours like swimming, walking, eating, sleeping, and interacting with my other turtle, looks normal). In the next link you can watch a video of my turtle, there you can hear the noise and look his altered behaviour: https://www.dropbox.com/s/p0sgknkh23jbg ... a.mp4?dl=0
Is this normal? or is a symptom of a possible disease?
More information:
Leonardo is a male RES, approximately 20-25 years old, I had him for the last 18 years (I think). He live with another turtle (with similar characteristics). I feed them everyday with a mixture of Sera Raffy P and Mazuri Aquatic Turtle Diet.
His aquarium have 125L of tap water (with water conditioner for turtles), the water in his aquarium is always at 25-27°C (79F), and his basking zone have a 27°C temperature, without air currents (to keep this temperatures I use an automatic water heather, and a ceramic lamp in the basking zone, I control the temperature with a aquarium thermometer on daily basis). I use two filters with sponges for mechanical filtration and activated carbon for chemical filtration. The basking zone have a proper UVB light, which is turned on 8-10 hours per day.
Thanks a lot for your advices!
EDIT: Extra (and maybe important) information: Both of my turtles are old (20-25 years old, one of them have at least 25y) but they are very small, this is because for a long time they lived with very bad conditions. They are living with the conditions said in this post for the last 2 years approximately. Before that they lived in a small plastic box, with a little basking zone, no filter, no heater, and for some years bad food (only shrimps). For the last 7 years (I think) they have been eating Sera Raffy P and Mazuri. Anyway, in that period of time they never had any observable or evident diseases. Only the last months one of them (Rafael, the second turtle in the video), had a injury by herpes virus (which was controlled and treated by a Veterinary).
EDIT2: Important: this noises are only made by Leonardo. He starts doing this the first weeks of this month, the video is from July 8th (it was the second time that he did it). After that he didn't seem to did it again since the last week. Is not constant, and it doesn't show an evident frequency pattern.
