Well, i have a 37 gallon tank with 2 clown plecos (3-4 inches), 1 bristlenose pleco (4.5 inches), 7 cherry barbs (1.5 inches), 7 neon tetras (1 inch), 7 pricilla tetras, (I dont know how to spell it, they are transparent tetras) (1.5 inches) , 6 platys (1.5 inches), and 1 swordtail (2 inches)...