Hi there, am off on the weekend to buy a canister filter for our oscar tank. Up till now we've had an in tank filter. Our tank holds around 70-75 gallons so what size canister filter should I be looking at?
Cheers Kell

Do you know want make the shop will have?I would strongly advise you to go for a filter that is rated more than your tank. In other words, get a filter that is rated over 100 gallons if you can. As you know, Oscars are very messy fish, any extra filtration is a bonus

I would go with 100g+ or 200g if you can . this will mean you wont have to clean as much too, and as OFL said oscars are very messy fish. dont forget it must fit into your cabinet so this will be a factor too. you wont need carbon so if shop advise you to buy dont bother. just use bio tubes and foam in the filter.

Thanks for that guys. Not sure what make they will have but will take your advice and go for one over 100g.
Cheers Kell

you should get the biggest one that you can afford. for a tank your size a fluval 405 or a fluval fx5 would be ideal.

remember you can never over filter your water.

Go for a filter rated for at least twice the size of the tank you have. So in your case at least 150g. The ratings you get with filters generally apply for community tanks, however a 75g with 1 full grown oscar will produce more waste than a 75g with community fish and then one top of that you have the fact oscars are messy. Go for the biggest type you can afford, you cant over filter a tank

Hi guys
Thanks for all the advice. Ended up only being able to afford a Fluval 305 (cost $325 AU or $280 US or 190 EURO) but I did find out that our tank holds less than hubby had worked out. It holds 66 US gallons not 75 like he thought. we're also running the internal filter which is rated at around 90 US gallons so between the two I'm hoping that will be enough for now.

And yes the shop did say that I needed the carbon, which came with the filter. They reckon that it helps to create the necessary bacteria, is this true?

Thanks again and cheers Kell

No rubbish. save your money you dont need the carbon. Keep it just incase you add any medication at a later date, carbon will help to remove this. it will also absorb ammonia, so is worth keeping. if you where to use it you would be changing it all the time as it will only last 2wks or so then it starts to leak all that its absorbed back into your tank. Its a good income for your local fish shop.))

I agree with marcus. Carbon will help keep your tank looking clean, however so will good tank maintainance like cleaning your filter regular (depends on how big it is compared to the tank but every 6 weeks or 2 months will do) and water changes (both are a must for oscar keepers). To have carbon in your filter you will down the fish shop every six weeks(according to some) buying more. Save your money