what happened: I was checking a closed pool for baby turtles or other trapped animals when i found two baby RESes, one was fine a had probably just fallen in but the other was sluggish and sickly. I released the healthy one in a lake across the road (its natural habitat), then i took the sick one to put in my rehabilitation tank (where i will keep it until fully recovered) after about 5-10 seconds it spat out some orange liquid, (possibly puke) i then noticed a brownish grey spot on one of its scutes.
closed pool conditions: pool had a layer of 90-100 degree water on the surface, underneath that it was about 50-60 degrees depending on depth, the water was filled with dead plant matter, some dead worms, spiders and lots of other dead insects and one dead toad. the dismal pool was covered with a dark blue retractable pool cover, so it was possibly hotter at 12 o' clock.
rehab tank conditions: clean, filtered water, some turtle friendly aquatic plants and animals (snails, small fish, algae) and one large basking area.
question: what should i do apart from taking it to a vet? or do i need to at all? what all could have caused the problems?
How big is your turtle? about one inch.
How long have you had it? about 6 hours.
What is the water temperature? 76.
Did you use a thermometer? yes.
Are you using a water heater? yes.
How much water is in there? about 45-50 gallons.
Are you using a water conditioner? only when necessary.
Are you using any filtration? yes.
What is the basking temperature? 85-90 depending on time of day.
Is there a basking light? yes.
Is there a basking platform that is easy to climb on? yes.
What kind is it or what is it made out of? a hard foam like material.
Is there a UVB light? yes.
What have you been trying to feed it? nothing yet but turtle pellets, bugs and aquatic veggies from their native habitat are present.
When was the last time your turtle ate? hasn't been long enough.
How big is the tank/pond/enclosure? 55 gallons.
Is the tank near a window? yes, but it's not open.
Is the tank in a room with a lot of activity? no.
Have you read the Basic Care section? yes.
Have you searched the forums for similar situations? yes.
Is there any other unusual activity/symptoms? he/she spat out a orange liquid when first placed in water, he/she has a brownish grey spot on one of its scutes.

