How did you build it? Do you have filtration? It looks like you're using a bubbler? Is it in the shade? Is the net to prevent bird or racoons? How heavy is the plastic you are using for a liner? How many gallons? What do you use for fish food?
I've use 2x10 wood build into a big box square, I have UV+filter+pump, aeration bubble for backup, pond liner 20 mil thickness, net will prevent bird and as for racoon they have try but failed, estimate about 500-600 gallons, goldfish flake for food.
