You said the reptile had two other stool passings that were more normal looking. Has he eaten since you've had him? If he hasn't, that could also be a reason this stool passing looks as it does. The reason the vet couldn't take this stool was bc it typically needs to be a certain consistency and solidified material to have a fecal float done. With that said, i think this sample could've been examined under a glass slide with a microscope bc it does appear somewhat suspicious. However a history of husbandry, feedings, needs to be considered as well.