2 weeks ago I got a 75 gallon tank on cregslist. it came with a 14 inch red oscar and a 10 inch asian upsidown catfish and a 14 inch pleco. the oscar rarley eats. only ate like 15 pellets he had a fight with the guy that got him out of the tank into the container. he has had all the fish for 2 years he has had all of them since they where babies too. I have tried turning off the light for a munite then quickly dropping the food in and running away. what do i do?