How much & how often are you willing to change water? This will make a gigantic difference in how much fish the system can support. And with Cichlids there's the added complication of potential aggression, so the exact species matters greatly as well.
Will depend on species, rock work, and how often you're doing water changes. If you're doing weekly water changes I would say very possible to have 20 in there given enough hiding spots.
Will depend on species, rock work, and how often you're doing water changes. If you're doing weekly water changes I would say very possible to have 20 in there given enough hiding spots.