Not only is the tank over stocked, it is also poorly stocked. I'll explain.
Zebra danios are very fast swimming fish which ideally need a tank at least 36 inches long to allow them the room to swim. They are also shoaling fish which need a group of at least 10.
Corydoras are shoaling fish which need to be in a group of at least 6. 10 gallons is not big enough for 6 of the 'standard' sized cories. There are 3 dwarf species of cory but these need a shoal of at least 10, and again 10 gallons is not big enough for this sized shoal.
However, you said in post #3 that the cory is actually a Synodontis petricola. This fish needs a tank at least 36 inches long, a group of at least 4 and hard water. All the other fish are soft water fish.
A single dwarf gourami might be OK in 10 gallons - but not with zebra danios in any sized tank. Gouramis are slow swimming, sedate fish which are stressed by fast swimming fish such as danios.
Shrimps are fine, though more of them would be better. However a gourami is likely to eat shrimps, babies if not adults.
So you have a mix of hard and soft water fish, fast swimming and slow swimming fish, and fish that will eat baby shrimps if not the adult shrimp as well. And you have shoaling fish in groups which are too small - zebra danios and the Synodontis.
It is difficult to know what to suggest. If you have soft water, the simplest option is to keep the gourami and shrimps and to rehome the danios and Synodontis.
Or you could upgrade to a tank at least 3 feet long. This would open more options - keep the gourami in the 10 gallon and move the danios to the bigger tank, increase their numbers and get other fast swimming fish.
The problem is the Synodontis. It needs more than just one, and ideally should be kept in a tank with other fish from Lake Tanganyika.