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Is overfeeding an acceptable way to kick up nitrogen while fish are small?
My nitrates are zero and my plants are getting chlorotic--I think it's all because my fish stock aren't eating and pooping enough. They're small (catfish fingerlings, minnows, loaches and crayfish), and the water is still quite cool.
I fed the cats this morning but the sinking wafers are mostly disintegrating on the bottom--and I'm thinking, "Great. At least this will kick up my nitrogen a bit." I'll look forward to seeing if I get any readings on NH3, NO2-, NO3- tomorrow.
Replies to This Discussion
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Permalink Reply by Pat James on
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I was always taught that you 'feed the tank not just the fish'. I know you are ddealing with a small tank so be carefulit does not get away from you. In my case, I have a 20K+ gallon swimming pool so I could almost drop a cow into into it and not get a major spike in ammonia.
My pond has had alot of algae and what you would consider phytoplankton. The stuff turns the water green but even in clumps has no mass to grab.
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Permalink Reply by Jeffrey Ihara on
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I'd be careful or you will wind up with super high levels. My plants are not doing so good either. in my case,I am resigned to just growing fish until I get the water mineralized.
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Permalink Reply by Sam Burton on
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Over feeding is always risky business. I believe some DWC proponents are practitioners of overfeeding, especially in large systems, but those are carefully monitored. An ammonia spike, if large enough and fast enough can leave you with dead fish in a hurry. I know from experience. Unless you have a VERY large system with only a VERY few fish, you'll get your nutrients soon enough. I promise you that catfish and crawfish know how to provide what you need.
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Permalink Reply by Vlad Jovanovic on
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Jeff, when you say 'chlorotic'...what 'exactly' do you mean..?
A general chlorosis (N) across their broad surfaces..? Intervenal chlorosis? Intervenal chlorosis on the older leaves (Mg), or on the younger leaves only (Fe)..? Or both...Or something else entirely...
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@Vlad: eh. just general yellowing, and no or very slow growth, even on the mustards. With zero readings on all forms of usable nitrogen it's kind of expectable. What I didn't anticipate is that this far into my heavy-handed feeding I'd still be at zero. The cats are growing though!
To be honest, though, I wouldn't have considered magnesium or iron deficiencies at all given the hard data I have on nitrogen being AWOL.
@Sam: I would have thought 14 adult loaches, 9 crayfish, 12 fingerling channel cat, minnows, and now three Japanese trapdoor snails would put out enough waste to get measurable nitrates in about 400 gallons of circulating water. ya think?
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Permalink Reply by Hank Paloci on
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I had the same idea. The weather here just got warmer and the tank is maintaining 80F instead of 70F. As a result, my fish want to eat 5x a day instead of 2x. I wanted to see what would happen with the extra food and liked the result ... I got a major fish and plant growth spurt but also a nitrite spike. Changing 5 gal of water twice a day for 4 days I only lost 2 tiny fish. Nitrates also spiked to 40ppm+ before coming back down. I used the waste water to feed my regular garden, my orange tree, and my wife's flowers, and they all had a growth spurt too. Nitrates coming back down (1+ppm instead of 5), and I think everything is coming to equilibrium. So feeding the tank (and the fish) more does chemically about what you'd expect. Keep a closer eye on the water chemistry than usual and it might work out like it did for me.
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Multiple feedings isn't really an option for me. My catfish hide all day and come out to eat like pigs at sundown only. They'll pretty much leave food alone and sitting on the bottom all day if it's there.
I've been sitting on zeroes for ammonia, nitrites, and nitrates for 12 days. I've been pulling out greens from the growbed to feed to the chickens to see if that would let the nitrates build up. I have been feeding pretty heavily at night, and usually there's still a bit of food on the bottom by sunup. I also have some activity in my sump tank that really should be liberating ammonia--the crayfish have been killing and eating my loaches leaving me with just picked-over skeletons.
For the record, I did see ammonia, nitrites and nitrates during the fishless cycling. Just not since April 18. My plants are living but not growing--with the exception of one radicchio in one bed and one cilantro in the other that are doing well and growing. Could it be that these two plants are bogarting all the nitrates? Seems impossible.
The water tonight is a bit less clear than usual. Maybe the last loach is putting a bit of bacterial load into the water. We'll see what the chemistry looks like in the morning.
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Permalink Reply by Tom Dumas on
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Jeffrey I have a system with similar amounts of FT water and I have 200 fingerling cats which produce just about what I need for now but the weather is cold and plants not growing that fast. My nitrates hover around 40 ppm to 80 ppm. Ammonia and nitrates are zero. I only have two beds planted, IBC, with broccoli, which are rather large, and assorted basil, cilantro, and as an experiment several tomato plants. I plan on adding at least, when the weather warms, 250 more fish to the tanks. Looking for the correct ratio of fish to plant can be tricky but most people have far less fish than necessary in their systems. Tom
Jeffrey Ihara said:@Vlad: eh. just general yellowing, and no or very slow growth, even on the mustards. With zero readings on all forms of usable nitrogen it's kind of expectable. What I didn't anticipate is that this far into my heavy-handed feeding I'd still be at zero. The cats are growing though!
To be honest, though, I wouldn't have considered magnesium or iron deficiencies at all given the hard data I have on nitrogen being AWOL.
@Sam: I would have thought 14 adult loaches, 9 crayfish, 12 fingerling channel cat, minnows, and now three Japanese trapdoor snails would put out enough waste to get measurable nitrates in about 400 gallons of circulating water. ya think?
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Tom,200 cats now and 250 more soon? Considering I paid $3 a piece for my 12, that would be pretty much breaking the bank for me. Are you harvesting your fingerlings yourself from a local pond or lake?
But yeah I definitely need more fish. I'll probably load up the tank with fatheads, which will ultimately turn into catfish biomass once the kitties get up to size. I also plan to toss in some bullheads, but I want to wait until my little channel cats are too big to fit in the bullhead's mouths.
Jeff
Tom Dumas said:
Jeffrey I have a system with similar amounts of FT water and I have 200 fingerling cats which produce just about what I need for now but the weather is cold and plants not growing that fast. My nitrates hover around 40 ppm to 80 ppm. Ammonia and nitrates are zero. I only have two beds planted, IBC, with broccoli, which are rather large, and assorted basil, cilantro, and as an experiment several tomato plants. I plan on adding at least, when the weather warms, 250 more fish to the tanks. Looking for the correct ratio of fish to plant can be tricky but most people have far less fish than necessary in their systems. Tom
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Jeffrey when I say catfish they are channel catfish fingerlings that cost me .30 cents each, 3 to 4 inches long. The most I've seen them sold for are .45 cents each. I guess what I call cats you call bullheads. Are talapia available in your area? Another fish about a $1.00 and great eating. These require warmer water however. Depending on whatever fish you get you want at least a one pound fish per 5 gallons of water. Any fish will do. There are many suggestions on ratio's and I go to the upper end when planted heavily but you must watch your water carefully. Tom
Jeffrey Ihara said:
Tom,200 cats now and 250 more soon? Considering I paid $3 a piece for my 12, that would be pretty much breaking the bank for me. Are you harvesting your fingerlings yourself from a local pond or lake?
But yeah I definitely need more fish. I'll probably load up the tank with fatheads, which will ultimately turn into catfish biomass once the kitties get up to size. I also plan to toss in some bullheads, but I want to wait until my little channel cats are too big to fit in the bullhead's mouths.
Jeff
Tom Dumas said:
Jeffrey I have a system with similar amounts of FT water and I have 200 fingerling cats which produce just about what I need for now but the weather is cold and plants not growing that fast. My nitrates hover around 40 ppm to 80 ppm. Ammonia and nitrates are zero. I only have two beds planted, IBC, with broccoli, which are rather large, and assorted basil, cilantro, and as an experiment several tomato plants. I plan on adding at least, when the weather warms, 250 more fish to the tanks. Looking for the correct ratio of fish to plant can be tricky but most people have far less fish than necessary in their systems. Tom
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I'd like to get into some of those 30¢ channel cat fingerlings, Tom! The outfit who sold me the $3.00 cats were selling them out as soon as they were getting them, they said it was because the aquaculture people are unwilling to part with their stock. I think it's because the growers (somewhere out in Imperial County) know they have a monopoly given the laws about bringing fish across state lines.
The bullheads I spoke of are regular black bullheads that I'd be catching from one of the local reservoirs. Not much to look at, but they are edible and make plenty of plant food (I presume).
Tilapia? eh--well I don't find them very good for the table. I'd rather have catfish.
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