8 ft diameter, 3 ft at deepest (shelves at 2 and 1 feet also), around 750 gallons.
It's a new pond, up and running only a few months.
We have a Tetra Bio-active pressure filter (mechanical and Biological)
We now have 5 fish. One we've had for about 2 months (about 3 inches) and the other 4 (plus the dead one) we just got this week and are about 2 inches.
Feed twice a day, only a pinch (we read they should be able to eat all of it within a couple minutes so we kinda judge by that)
Can't think of anywhere they could injure themselves. It's a liner pond, there are baskets for the plants and a tilted pot to hide in and that's it. There are rocks along the edges, but the ones the fish can get near are smaller river rocks.
We did not quarantine the new fish.
We test the water once a week today Nitrates: 0, Nitrites: 0, Hardness: 150, Alkalinity: 120, PH: 8
We have water changes once a month and we use Safe to remove chlorine and ammonia, but we top off the water about once a week without treatment to account for evaporation.
We live near hills so we get predators like raccoons in the neighborhood, but our 2 huskies usually keep them away (the dogs hate water so they don't go near the pond).
I did just notice today that we have VERY TINY white bugs hopping off the surface of the water. Never seen those before, not sure what they are or if it matters.
Let me know if you need any more info and thanks for your time!