Yes, let us know exactly what kind of fish you have, until then it's impossible to say if you're understocked or not. For all I know, the danios could be 2 inch zebra danios or 4 inch giant danios. What about the plecs? When you say small, does that mean they're small but growing, or that they stay small? Oh, and this could be just my ignorance, but what is an ID shark?