Those people are wrong, you definitely shouldn't keep any fish in a 2.5 gallon. I have a 5 gallon myself and I couldn't imagine imprisoning any fish in a space half that size.
How tall is the divider? Is there water flow between them? If the answer is yes, shrimp will get to the other side and end up as lunch for the betta. They have legs and will find themselves everywhere in the tank unless the divider reaches several inches out of the water. Bettas are more predatory than similar-sized fish and will actively go for fry, shrimp and eggs they find that aren't their own. Small shrimp like neocaridina will in all likelihood be gladly on the menu for them, especially in such a small space where they might not be able to hide.
I’d medicate the whole tank for parasites. Praziquantel is pretty mild when used as directed and then you’ll know all your fish are parasite free starting out.
I would get some freeze dried blood worms. Add a very small pinch of the meds to an ounce or so of water, stir well. Then soak/stir the worms in the medicated water for about ten minutes or so. This gets the meds in the food. Hopefully he will eat.
Anything dried should work. What you are simply doing is rehydrating the food with medicine in the water.
I thought you were going to treat him days ago? General cure wouldn’t be my first choice for cloudy eye but since you started it, I’d finish the round and see how he looks. That medicine will work through his skin and gills. It doesn’t have to be mixed with food but is fine if you do.
That would be great. Some tetras can be ok tank mates with bettas of the less aggressive varieties like black neons or cardinals. Some varieties like black skirt can be fin nippers so do your research.
. On an unrelated and cool note I am going to a new LFS soon. Will be picking up bloodworms. His eye doesn’t seem cloudy. Shows little internet in food though.
