I’ll second that, I had a school of pigmy corydoras, and they were one of the best fish I kept, sadly, they are happiest with a sandy substrate, and it appears the OP has a gravel base, which will harm their delicate barbels, so I wouldn’t recommend them.
OP: You need to get a test kit, and establish what type of water you have, as certain fish will cope best with particular pHs of water. Living in the High Peak, I was blessed with very acidic water, so was able to keep south american dwarf cichlids (A breeding pair of Apistogramma cacatuoides amongst others) , which are brilliant little fish, colourful and full of character, but not suitable for more neutral water.
Once you’ve cycled your tank, with a spot of ammonia, and have established the pH, people will be able to help you out with ideal fish.