oscars arent generally very aggressive as long as they have space and are fed well, and im propably gonna get rid of the pike because hes always causin trouble, so i think the lima will be fine. the 10g is super clean, i just put a hob filter from my 100g on my 10g(rated for 60gs, it pumps 330 gph). My only problem now is my lima still wont eat. im hoping he'll start eating within the next couple days.