hi i was wondering if my baby pacu are showing signs of stress , i have 2 oscars 1 is about 21/2 inches and the other is about 3 inches and i recantly bought 2 pacu about 3 or 4 inches in size they are all in the same tank about 4o gallons. the pacu are quite larger than the oscars but they are always swimming like there following each other doing loops and looking like there on a roller coaster , they act like the oscars arent even there but should they always be this active or is there something that i might need to know about