would 4 sterbai cories be able to go in a 15g tank along with 5 female bettas?
I go by the old rule of one adult corydoras per 5 gallons which is probably conservative; for a 20 gallon four should not be a problem. Last winter I raised ten (10) C. sterbai juvies in a 6 gallon. Currently I am raising about 18-20 C. sterbai (6 albinos and the rest regular) in a 10 gallon and I have about 7 adult C. sterbai in my 30 gallon.
Juvie C. sterbai in 6 gallon
Roy 75 Gallon, 2X55W AH Supply CF 8800K, 1XFluval F&P 2.0 48"/59W, 2X Marineland 350 Magnum filters; 45 Gallon Tall, 96Watt AH Supply CF 6700K, 1X Marineland 350 Magnum filter; 30 Gallon Long; Fluval F&P 2.0 36"/46W, Marineland C-220 filter; 20 Gallon, 1X26W AH Supply LED kit, Marineland C-160 filter; all with Press. CO2 and (Calcined) Montmorillonite Clay Greater Seattle Aquarium Society (GSAS)