qustion about a 10 gal tank

White clouds are far too big for 2.5 gallon tanks. 5 of them will really need a minimum of a 5 gallon tank to themselves.

Now if you can keep the temp of the 10 gallon tank to around 74F to 76F max, then I would suggest that you put the 5 white clouds there with a single male betta and 3 cories. That is it no more. That will be a healthy tank and with proper water changes (weekly) and possibly some live plants things will work out fine. Loose the cardinals in that tank though.
 
The trick with a 10 gallon tank (as with any smaller tank) is to make sure not to over stock it. That is very easy to do. The fewer fish you can stand having in their the better it is for them.

I consider my 10 gallon almost overstocked but it is heavily planted and seems to maintain a nice balance. There is a lot of maintanence goong into it as well. I have 5 white cloud minnows, 3 cory catfish and 1 false SAE. I keep the temp near the lower end of the 70's F. ANd in the winter I keep it nearer to 69F.

A good option is a school of fish the size fo the smaller tetras, say 6-7 silver tips or cardinals and 3-4 cory catfish. With weekly water changes (after it has cycled) you should be able to keep that healthy. If you add a betta to the mix I would drop it to a max of 5 tetras.

A few ghost shrimp, say 3 or so, won't really affect the bioload.
 
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