I have a small pond with fountain in the middle. It’s about 1500 gallons. I use a 5200gph pond pump in the deeper end and a go plus bio filter 4000 gl with 13 watt us light. Although I think the light isn’t working...do I also need to use an aeration device? The water falls from about 4 ft into the pond. The pond is about 4 ft deep in the deep end and 1.5 in the shallow end. I’ve had my fish for about a month and they seem happy, but I’m not sure if they need more air. Also, after reading this forum I fear I have too many fish. I have around 20 but they’re all fairly small right now. If they grow an inch or so a month there is plenty of room for awhile yet. I live in MA so warm weather is only 6 months a year. How long did it take before your fish would eat while you were standing next to them? Mine hide in the bottom until I walk away and then they go crazy . Thanks!