Living in the Dark

Every 15 minutes, the bell siphon in my Aquaponics media bed flushes the flood and drain system, aerating the water for my goldfish below. The fish live in the dark. 

Using camera flash during flush mode. 

I feed them once a day. Other than that, I generally don't think much about them. I can't see them well without a flashlight, so they've gotten little attention in the few years I've kept them.  

These comet goldfish are from the local pet store. They are low maintenance and make a lot of fertilizer (read: poop a lot). At their present size, I think they're ideal for this cool-weather system.

The roots of the plants keeps their water clean, and a small pinhole at the bottom of the siphon (in the media bed) provides a constant trickle of fresh water in between flushes, which keeps them healthy.

Swimming around the water pump prior to flush mode.

These goldfish are about 4" long.

One huge benefit to the fish living in the dark is there is no algae growth. With the absence of direct sunlight in the barrel, I don't have to deal with algae killing the roots of my plants. Above the fish, the media bed fills to a couple of inches below the rock surface, so no harmful algae grows there either.

Someone asked me, "Are they happy?" It's hard to really know, but they've tripled in size, haven't gotten sick yet, and they eat well.