ok so i have a 125 gallon with an emeror 400 and a penguin 350 is that enough filtration have 5 baby oscars (biggest is 3 inches) and if not how big of a canistor filter should i use im planning on buying a 100 gallon capable canister fluval something not sure what model but it does say up 100 gallons would that be enogh

I have a 150gallon tank and use a fluval fx5 400 gallon pump. this works well for me. i think pump power should be at least twice that of your tanksize and if poss 3 times or more. This means you are not always cleaning it out. 125g tank with 5 oscars will mean you are overstocked very soon. you will be changing a lot of water to keep conditions good very soon so be aware. i am overstocked myself with 4 full grown oscars and change 50gallon twice a wk. I am not saying dont do it as I have done it myself but just want to make you aware that keeping water condition well is hard work.you may even have another tank or intend not to keep all 5 but i wrote this just incase.

they don't sell those filters in the UK. However, I think that the Penguin 350 is okay up to 70 gallons, and the Emperor 400 is okay up to 40 or 50 gallons, I think. So you have just about enough filtration, you are really borderline. To answer your question about is this enough filtration for five baby Oscars? Five small baby Oscars probably yes, but remember it won't be very long before these five baby Oscars are 8 inches long, and a 125 gallon tank will not be big enough, you'd be looking at more like 300 gallons.

if you're serious about keeping large fish, forget these hob filters, you must have a large aquarium with either large external canister filters, or even better, a sump filter. However I am talking in excess of 100 gallons. if you're not able to get your self a very large aquarium, forget getting several Oscars, you just haven't got the room.

i find that for hob filters the best you can get are the aquaclears. they allow you to customize the amount of biological and mechanical media that can put in to them. the penguins are great for smaller fish but if you use hobs for oscar you really should use the aquaclears.

now on my tank oscar tank i use four aquaclear 110's each rated for a 110 gallon tank(they move 500 gallons per hour each) and a 40 gallon sump with a submersible pump which moves 950 gph at a head height of 5 feet. this combination is enough for me to keep four oscars 2@about 12 in and 2@ abour 6 in, a 6 in c.a.e. a 5 in rainbow shark, a 2 in convict and 2 jack dempseys 1 @6 in and the other @ 3.5 in.

is still have to do 2 water changes a week of about 25% to keep my nitrates below 25

in short i think you are going to need a lot more fitration than what you have now. an fx5 by fluval along with your hobs are really what you should be looking for or a sump filter in the 30 gallon range