We looked at and bought a house in January when there was snow on the ground. After closing the previous owner told my husband not to break the ice on the goldfish pond and exsplained we were now the owners of a outdoor goldfish pond. I have tried to read up on maintaining this pond and we have done work on it. It was half anove and half below ground. We could not see any fish. We knew we lost 3 fish. So after it warmed up we started emptying it and found I think 6 about 3 inch goldfish. We put them in a container and cleaned out the hard shell liner. Dug a hole and put it in the ground. Filled it with water let it set for 24 and added the fish. There is no filter. It. Does have a pump with a frog fountain. I have sence added a couple iris, another plant,3floating plants Im not sure what they are and 12 dwarf lettuce plants. Today Im adding barley straw because the water is so green . Im not really wanting to add chemicals but not sure what else to do about it. Do we need a filter? We think its about 100 gallons. I looked on line and found the hard liner that looks like ours to determine that. So I could be very wrong. It has plant shelves so I think the formula to figure out how many gallon seems to be way too much. We are really enjoying this added surprise of this pond with our house. But really need help on maintaining it. Any and all help will be appreciateýù