Relax please. Live with it for a while.

Pictures? You can drain a pond with a trash pump, but it will fill up again. Is there a dam?

Did you buy the property knowing it had a large pond on it? And yes, relax and live with it for a while. Ponds are usually considered an asset to a property.

What wildlife is currently living in or off of the pond? Have you seen copperheads yet? The green is normal- algae blooms start in the spring. Some folks choose to remove or prevent it, others let it grow.

Is it a stand-alone pond, is there a water source that feeds it?

If you do decide to remove it at a later date, and if you can, depending on what lives there that may be protected.... no, don't try pumping it out down the road- it would just refill and probably peeve off the local gov that takes care of roads and ditches. You would need to fill in the pond completely to keep it from retaining water.