if ur goin somewhere like pecto they have the max size the fish can reach (witch is pretty accurate) and the appropriate tank size, which actually isnt acurate at all. u want something that doesn't get any larger then 3'' or so. tiger barbs are pretty cool and easy to care for smaller fish imo. anyways, good luck!

well to be quite honest m8 you cannot go putting a poor old oscar in a 20 gallon tank thats just a bit stupid i got a 70 gallon tank and its my 1st oscar tank and i only got 1 oscar in there i wants to have to but my tank aint big enough for the pair, so il definatly say that the oscar shouldnt go in your 2o gallon, as for the silver shark goes i do not reccomend that you put it i9n a 20 gallon tank as they too can get reaaly big and soon enough he will be doing all the bullying in your tank,
but i would try and get a bigger tank if you want to continue keeping oscars and believe me its 110% worth the wait

ash

i was about to put a oscar in a 48 but when i did more research i found out that you should put one oscar in a 55 gallon after that you can get a 60 gallon then that would be good.

i was about to put a oscar in a 48 but when i did more research i found out that you should put one oscar in a 55 gallon after that you can get a 60 gallon then that would be good.