I'm pretty certain that is a Catathyridium jenynsii
which is one of the true freshwater flounders, and one I ve kept. they are however sub-tropical so the temp should be between 20 and 26c
the main problem keeping any flounder is feeding, most are hard to feed and every one I've kept stops eating at one point for no apparent reason and subsequently dies. my C.jenynsii managed to stay alive for 7 months before stopping eating. the diet was (frozen) mysis, prawn, (live) bloodworm, glassworm and mealworms.
an adult should reach 23cm but I doubt that will happen in captivity.
the best set up is a fast flow tank, like a river tank, with lots of round boulders and plenty of O2. substrate should be sand as they hide in it so an area of the tank should be clear of boulders for this purpose.
your 10g is probably a bit on the small size and I've kept all my flounders in no less than 30g