Backyard Aquaponics
A place to discuss aquaponics

This may be a stupid Q but with cheap goldies in an IBC do they really require much light.
thinking reason.... clear/semi clear IBCs allow light in which can produce algie, so we seal them with paint and insulation material to stop that. Some wizards here even bury their tanks.

I think I am answering this for myself.....but it would be nigh impossible to completely seal all light being transmitted inside right.

But do fish require light to survive?

I have a large Murray Cod in an aquarium, indoors, in a very dimly lit area. It's now about 12-13 years old from fingerling and never seen sunlight.

There is no light immediately above the aquarium, but there is a couple of 4ft, cool white, T8 flouro tubes about 6-8ft above and a few feet to the side of the aquarium, so a poofteenth of f'all light really, and they are only turned on for a few hours a day if I'm working out the back of the shop.

She grew extremely quickly, she got to about 600mm within 3 years, and had laid two batches of eggs by the time she was about 4 years old... so I'm guessing she's happy with no light.

I also have half a dozen 4yo, 1.5kg Silver Perch in the IBC display system at the front of the shop. They get no direct sunlight, but do get indirect light through the shop windows. There is a 600w HID light over the grow bed, but none of that light directly hits the FT.

P.S... I also have a single barrel system at home that is over 6yo and has been powered by 6-7 goldfish at any one time. There is only a small inspection port at the front of the barrel, so very little direct sunlight gets into the FT, just a couple of hours in the late afternoon in summer, and very little or no direct sunlight in winter.

The goldies do alright, they grow well, the only time I lose them is when they jump out occasionally (I have been meaning to put a bit of gutter guard over the inspection port... for the last 6 years), normally in winter when the water level gets up to and overflows at the insp' port due to rain (I've also been meaning to put an overflow a couple of inches down from the insp' port... for the last 6yrs).