I am making a 700 to 720 gallon pond (above the ground). Measuremeants are 8ft long x 4 ft wide x 3 feet deep. 1ft will be below the ground and 2 will be above. It will be housing 7-8 Oscars. I need to get a better understanding about ALL the equipment that will be needed to keep this pond clean and crystal clear, as well as my fish save and happy! Shallow plants along the edges of the pond will be added as well (and will be unreachable to the Oscars).

8 x 4 x 3 x (7.5) = 720 gallons.

I would approach this project in the same way as if you were to keep koi carp. both fish are incredibly messy and therefore need very good filtration. I assume that you're living somewhere fairly warm, if not, you're going to need heating all year round, that's not going to be cheap, several hundred £££'s for a good heater. However, there Oscars living in the waterways of Florida that thrive very well. However, you have to remember that these have adapted to the conditions, I don't think that would be a good idea buying an Oscar straight from a shop and plonking it in a pond that isn't very warm.

check this link out, it will give you an idea of the kind of filtration that would work well on a pond.

www.cdaquatics.co.uk/catalog/cold-water-...-media-c-143_77.html

i agree there with you ofl if your gonna be purchasing an oscar from an aquatic store its not advisable to put it straight into a pond thats much colder as the poor old oscar will get a right shock and with oscars being messy feeders i ignored this when i got my oscar and therefore had to buy another 2 internals once i realised how messy feeders they really were and now im thinking of purchassing one good external filter, if your doing this i would recommend the best filtration that you can afford i