Okay since I have filtration issues I was wondering if I could put a fluval filter that's made for 80 gallons. Its a canister as I am planning to upgrade to a larger tank so I don't want go spend a whole bunch in the 55 gallon

For Oscars you need to at least double the filter capacity. Example 110 Gal tank should have no less than 220 gal filter capacity.. I would run 3 times the capacity.. 360 gal filter for a 110 gal tank with two oscars max.

you have a few problems all at once. 1st is your tanks to small for the number of fish you have. 2nd is you are under filtered. adding an extra filter will take 6wks to cycle, keeping the water in good condition for 6wks with 3 oscars and a plec is going to be hard work for anyone. you need a larger tank and large filters now. even if you had a 150g sitting in your house you will still have a lot of work on your hands.

Yea I no but I'm looking for a larger tank may have it by mid next month but meanwhile I wait for the other tank to cycle as I am 200 short from a new tank. I have someoneholding a 180gallon tank for me so image have to wait on it

In that case any filter you can put on it is better than just one.