I'm going to be changing up my 28 gallon soon - platys out, angel and tetras in. I would like a school of cardinal tetras. I know that the angel could eat the cards, but I'm going to buy the angel small, and I'll just have to be ready to trade him out if he ever starts munching on my tetras. I've seen tanks that have kept angels and cardinals successfully, so I want to give it a try.
The tanks is 28 gallons, will be moderatly-heavily planted, and over-filtered. How many cards could I keep with the angel? I'll also have amano shrimp. If I can't find another tank for the two platys, they will stay also.