I have a long 20g with 4 long finned black tetras, 4 black tetras, 1 common pleco (which I have a plan for when it gets to big) Is this to many fish or am I ok? The reason I ask is because before yesterday I only had 2 long finned and 3 regular black tetras and the common pleco and the pleco was fine moving around slowley and peacefully but now since I added the two more long finned and one regular black tetras is seems ALOT more active and won't stop moving around, I guessing this is because the new fish seem to be in his spot that he had once claimed as his and when ever he stays in one place at once all the fish start crowding him and swimming around him and whenever he moves they don't get out of his way so he starts going crazy. Is this stressing him out or do you think the tetras will calm down once I turn the light on tommorow?