I have a 20gal tank with 1 angel, 1 clown pleco, 5 serpae tetras and 5 zebra danios. Would I be able to put 2-3 shrimp of some kind in there? My mom would really like some shrimp...but then again, she wants another angel and 3-4 cories in there...she doesn't understand the whole overstocking idea 
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