Hi Tanya,
First of all... geckos can not just get crypto, it has to come from somewhere.
Have you gotten any new animals in recently?
Is impaction even a possibility? Substrate?
To what extent is her belly swollen?
You say she is eating and pooping just fine, definitely not a sign of crypto. If she has nasty runny stools, starts to regurge, or stops eating it might be time to worry.
As far as the notion that a swollen belly means crypto... not entirely true. I have actually talked to my vet about this (very good reptile vet, breeds boas too) and he says that lizards/geckos do not show the swollen abdomen nearly as much as snakes, and some may not show any swelling.
Now to address the black mass... probably just her liver, but could be an impaction, etc...
My recomendation to you is this:
1) Quarantine all geckos that have been exposed to her.
2) House her alone so you can moniter her stool consistency and eating habits.
3) Go buy some latex gloves and use them when you handle her or her enclosure, etc... Dont depend on hand washing alone, it's much better to throw the gloves away rather than rely soley on soap and water. This is purely precautionary at this point.
If you really feel something is wrong, then by all means bring her to the vet; but if you think you might be jumping the gun a bit I don't see any reason to bring a gecko to the vet that is eating/pooping normally.
A vet trip never hurts, just saying it may not be neccessary.
I hope everything works out for you.
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-Ross Payan - www.LeosAnonymous.com
Leos Anonymous
Red Striped Tangerines, Carrot Tails and Screaming Amel Fat-Tails