Red1313

Would a stock tank with at filter work as a koi pond?

lilFishyfish

How many gallons? Would it have a light and gravel?

Red1313

Hmmm... it would be >100 gal. Adding some gravel to the bottom could be done. As for light, it would depend if the tank was outside or the basement.

PetSmart

Yeah it would . . . My family has a friend who has a big tub in his basement with large catfish in it. An option for something of that size would be a sump. A pretty basic design is used on that catfish pond ... I believe its a 40 gallon plastic pool raised up on some scaffolding and partitioned with media. A pump pushes water up into it, and a hole is drilled in the side and it falls ~2 ft back into the pond.