I have an aquascaped 46 gallon bow front tank, it has lots of plants and plenty of cover etc. but still lots of room. I have ghost shrimp, a few snails, plecos, algae eaters, and a patriot crab, I really love Tiger Oscars and I was wondering if I put one in this tank if as it grew (I would get a tiny one) it would eat everything in the tank?

Most suggest at least a 55 gallon tank for an Oscar, as they get 12 inches long. They are a big fish and produce a lot of waste and will eat smaller fish. I would almost guarantee that all the shrimp would get eaten and possibly the algae eaters.

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50 Bowfront, 2 Acei, 2 Yellow Labs, 1 Orange, 1 Albino, 2 Blue African Cichlids
30 Gal, 3 Fantail Goldfish, 1 Black Ryukin, 1 Common Pleco
20 Gal, Mollies, Platies, Cories, Algae Eaters
15 Gal, Swordtails, Balloon Mollies, Rasboras
10 Gal, 2 Knight Gobies
10 Gal, 2 Bolivian Rams
1.5 Gal, Male Betta

It won't be convenient since the Oscar needs a lot more room and will eat anything that can fit it's mouth.

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Oscars were my passion for many years, each was in a 40gl breeder tank. You should be fine with your tank. This is not to say a larger tank wouldn't be good when it reaches full size. Even in a larger tank they tend to hang out in one part of the tank and do little swimming around. Tall pieces of driftwood are good, and a tall plant or two, they'll hang up alongside them.
The ghost shrimp will indeed be likely to be picked off as snacks, but at 5 for a dollar they are good to put in there, as well as the occasional feeder fish.
I never had any eat pleco's, and the crab may get picked at. Do you have true Chinese algae eaters? Snails are not likely to become a meal either. They may hold there own for a little while, but if not feed regularly the Oscars may go for them. Oscars are truly voracious eaters, mine would eat so much it would have fish sticking out of it's mouth, laying on the bottom of the tank trying to eat more.
One of the most common diseases will be Hole In The Head, so read up on prevention for that, but that is usually seen when full grown.

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"Buddha in your tank"

A good feeder fish for Oscars is gold fish and glo-fish something to do with the colors..

It will likely destroy every thing you have in your tank.

There is a lot of debate about the size of tank an Oscar needs so I'm not trying to disrespect anyone else's opinion but personally I think your tank is too small. I saw a tank of Oscars at a public aquarium that people had 'donated' because they had outgrown their tanks. Some of them were really huge! One of them had lived in a tank just like yours but had gotten too big. Of course not all will grow to the same size but I think it's better to give fish room to grow and be comfortable. I'd rather start at 75 gallons for a full grown Oscar but at least a 55. You could start off a young Oscar in your tank but they grow pretty fast so I'd advise you got the tank first.