what kind of Cory is this

I think those are the ones I had - false juliis? Or maybe real juliis

What he said!!!
From what I've read julii Cories look very similar to several other Corydoras species, but aren't very common in shops. C. trilineatus is the one that I've read are the most common, and these are often sold under the names "Three-Lined Cory," or "Leopard Cory." Unless you know where your lil' fish was caught, you may never know for sure, but my understanding is that care for them is very similar - so it may not matter. . . either way, good luck with the cutie-pies, and welcome to TFK!

Honestly though, they're all pretty much the same as far as care is concerned.

Thank you very much, actually I changed my substrate to sand just for them.

Perfect - gotta keep those lil' barbels safe! Good luck finding more to add to their number! ^__^