My Red Eared Slider turtle who is now 6 years old has been a healthy happy little turtle up until the past year. His color on his shell and skin has started to fade and he has discolored patches on his red stripes. When he swallows fruits or vegetables I have noticed him immediately afterwards coughing A LOT of up bubbles. I'm not sure what would be causing this. I'm afraid it might be an internal illness or infection.
He is still eating well and is active, but he doesn't seem as lively as he once was. Part of this might be because he was separated from his brothers who were biting him and causing gashes. His wounds have healed, but he hasn't seemed as healthy since and now he cannot socialize like he used to. I used a reptile antibiotic to treat his wounds when they were still fresh. His overall skin also was very pink for awhile and still sometimes looks pink. When I took him to the vet they couldn't figure out what was wrong with him. I haven't had much luck with vets, they usually tell me things I already know about my turtle and they don't seem very knowledgeable on diagnosing illnesses.
Does anyone know what might be going on?
He lives in a 60 gallon tank with his two brothers. They are each about 6 inches big. His two brothers are on the other side of the divider that splits the tank in half. A thermometer is in the tank automatically warming the water up to its set temperature. He has a basking area, warming and UV light, water conditioner is used to treat the water, fluvial water filtration system, and I clean the tank every other week.
If anyone knows what might be causing these issues please let me know!