Predator fish compatability

[Dare On]

I have a 90 gallon tank with 2 aquaclear 300's running. I currently have an 18 inch long clown knife in the tank that I have had for about 5 years. I am considering adding a 5 inch long silver arowana to my tank. Will these two predator fish get along okay with each other? I have a solid top on the aquarium so the fish cannot jump out. Is this a bad idea or should I have a larger aquarium to do this? If worse comes to worse I would consider getting rid of the clown knife, but will 90 gallons be big enough for the silver arowana as I know they grow big and fast.

Thanks for any help on this matter.

 

[drobbins27]

I think Aros need atleast 125.

 

[G_Sharky]

Arowana's stay pretty much all it's time near the surface and I believe that a clown knife is a bottom dweller, so i think it should be fine, i would put them together but that is just my opinion and I can't guarantee anything. I know it's cruel but it would kinda be cool to see them scrap, it's like godzilla vs. some giant ants or something

 

[CFC]

I wouldnt advise buying a arowana without having at least a 180 gallon tank, arowanas are fast growing and even a tank this size will only give you a couple of years tops before you would need to upgrade to a 360g or bigger.

The fish are compatable but i would be worried about the size of the arowana, it would be better if you could get one around the same size as the knife fish as at 5" the knife may see the arowana as food.

 

[ryan]

As CFC said, nothing less than 180 gallons for a Silver Arowana and even that will have to be upgraded very soon. Then it will need 360 gallons or bigger to house it permanently.

An 18" knife is also going to see most fish as prey, so i wouldn't advise getting any fish smaller than 15".