My 30 gallon tank and fish

Question
Hi,
I was wondering if you could tell me if it is ok to keep a 12in. needlenose gar, a 7in. tiger oscar, and a 5in. albino clown kinfe fish in a 30 gallon tank with to 40 gallon filters running and how offten would i have to clean it? Thank-you very much.
Austin

Answer
Hello Austin
You are unfortunately heavily overstocked for a 30g tank. I know the general rule is 1 inch of fish per gallon of water - where you're at 24 out of 30, but the individual requirements of your fish mean you need something in the 75 to 90g range. None of them can actually comfortably live in the 30g even on a solitary basis.
The clown knife can get up to 24" easily, the gar can exceed 3 feet and an Oscar anywhere between 12 to 18". Based on their adult sizes you can see why you need a much larger tank.
Your best bet is to either aquire a larger tank relatively quickly or see if you can give the fish away - both gars and clown knives are not really suited to home aquariums; in fact most clown knives kept as pets are juvies. The Oscar on the other hand is a captivaitng fish and is quite intelligent. In a pinch, you could currently house it in a 30g and upgrade in the following months - as they reach a manageable size.
As for filters and messy fish, the idea is to always go at least a size or two higher than you need and to get your water to turn over at least 10 times an hour. For instance, a 30g tank would need a 300gph filter - so something like an Aquaclear 300 or Penguin 300. This number is negotiable if you are using a canister. I personally run dual filters on all of my tanks - a HOB (like a bio-wheel) and a canister.
As for how often you are to clean the tank - if you're feeding frozen or live food - between 2 and 3 times a week - otherwise weekly should do it. But I strongly recommend you re-house your fish.
Good Luck
Shawn