Tuesday, February 22, 2011

Night fish pics

Getting ready to go on my annual snorkeling adventure to the Virgin Islands, and I was playing around with the underwater camera and lights last night in my pond. It was pretty cold, and I put on my waders and just sort of lowered the camera into the water, so the photos aren't all that great, 'cause I couldn't really aim through the viewfinder, but some of them turned out OK. The water appears to be a little murky. That's partially from me stomping around in my waders, but it's also been very warm the past couple of days, and the algae has been very active. Once the water plants are able to kick into overdrive, they take up any excess nutrients, and the algae settles down to a level that the fish can manage.

I was hoping to get some pics of catfish, but they are still very small and very skittish. I'll try again during the day.


Future_Farmer said...

That looks really cool, is it the pic, or is the white ,koi?, really big? anyways love what your doing. I started my aquaponics system with no experience other than about 9 months of hydroponic growing. have you found a good fish/plant ratio? or maybe inches of fish/plant ratio? I currently have 2 herbs and about 10-13 inches of fish and plants seem to take up every mol. of nutrient available

Brian Naess said...

The koi is pretty large. It's probably at least 5 pounds - maybe more - about 24" long, I'd guess. He's been in there a while.

Because of my water plants in the pond, I've never had to worry about plant/fish ratios. The water plants seem to take up as much of the nutrients as they want, yet leaving enough for my growbeds to be happy.

Now, with my new, smaller sand system, this may be more of a factor.

In general, though, I think people generally speak in terms of how many fish you can have per gallon of water in your fish tank. I'm not sure that really makes too much sense, in my opinion, though, as it seems to assume that the growbeds are filtering out nutrients and converting ammonia into nitrates at a constant rate.

One of the things I'm most interested in seeing with my sand beds is if they are more adept at filtering the water than hydroton or gravel. My guess is that they will be, and as a result, I shouldn't have to filter the volume of water in the fish tank as often as I would if I were using gravel/hydroton. The only way to check would be to measure the nitrates going into the grow beds and coming out and compare those measurements against my pond-based system.

I haven't done any water testing at all in my systems, so I'm not sure I'm going to get that crazy about it. But, if I find a good deal on a testing kit, I might try it out, just for curiosity's sake.

Back to your question, I generally try to get as many plants as I can into the grow bed. I usually overseed and then thin out, once they get a little bigger and I can see which ones seem the strongest. I think that so long as your grow bed volume is approximately equal to your fish tank volume, you can plant as much as you'd like. One of the miracles of aquaponics is that plants seem to thrive off of nutrient concentrations that are far less than what they'd need in a classic hydroponic setting. This is because of the form the nutrients are taking - they are natural and therefore more bioavailable.

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