Can I add more fish?

They all would come from seperate suppliers so they would get added in stages and I could stop if I start to see nitrates at any point. This sounds like a huge bioload but why would I add Nitrates instead of fish?

Dosing nitrates is easier than relying on nitrates to build up from fish waste and uneaten food.

IMO you would be far too cramped any more fish.
 
I was looking through "The Ecology of the Planted Aquarium". It brings up a good point; the aquarium relies on mechanical devices to protect the fish. When a filter or heater fails it will become a problem much more quickly the higher your stocking.

Also, unless the fish wastes and uneaten food are quickly being cleaned or converted to fertilizer the tank can get anaerobic.

I guess if you imagine a ball on the top of a hill; that is what an aquarium is. The higher the fish stocking the steeper the slopes. If the ball starts to fall it will be harder to catch on a hill with steep slopes.

I am trying to find references to the fate of hormones in the aquarium but so far I have drawn a blank.
 
IMO you would be far too cramped any more fish.

I have been watching the behavior of the tank and I think another school of tetras would be too much. I think there would be problems with everyone finding space. Right now I have two lemon tetras that chase each other. The danios, cories and platies do pretty well. Once I planted the tank the danios completely changed behavior. They are really mellow and hang out around the plants. They have stopped schooling. They like to play in the java moss.
 
Fish are not just NH3 factories, their wastes contain all the breakdown products of their food which they did not or could not absorb for their own metabolism, these can be sulfur compounds and organics, neither or which we can measure easily or cheaply. They secrete hormones which while in nature would be flushed out simply remain in the water and build up. None of these are good for the fish but sadly we cannot measure them. But all is not lost. We can measure the NO3 that is produced from the NH3 that they secrete and based on this, we can make a hand-wavey generalisation about the other pollutants in the tank. To my knowledge, no one has actually measured the precise relationship between meausured NO3 from fish secreted NH3 and concentration of fish derived pollutants, but it doesn't matter, we can choose a benchmark NO3 level, like 20ppm and adjust our maintenance and water changes accordingly.

So NO3 is not just the non-toxic (in the short term) end product of 'cycling', it also allows us to have some idea of the level of pollutants in the tank.

Thank you for reminding me of that article. I had read it but this part did not stick.
 
...There is lots of other unmeasurable products of fish wastes, such as any number of organic compounds including sulfur, they also secrete harmones that need to be removed with water changes. None of these are good for fish or invertebrates. If you need nitrogen add some flourish nitrogen or something similar. Hope this post makes since and doesn't run together lol.

Great post---very informative. Thanks! Hypothetically speaking, could those problems be solved by over-filtering and an aggressive water change schedule? I'm not looking to overstock---sounds like too much work!---just curious.
 
My LFS has a 250 gallon aquarium that is the most over stocked thing I have ever seen. Imagine 30 people in your bedroom. All of the fish are quite large and there is no where for them to go. I asked about it and they have a large external filter and have to gravel vac every week. When they gravel vac the substrate is anaerobic and black. It creeps me out to see.

The owner is quite proud of it of course. There is not a single plant. I might be able to get a picture one day. There must be 40 Oscar/plocostomis sized fish in there. All different varieties. I don't know anything about large fish so I don't recognize the species.
 
Great post---very informative. Thanks! Hypothetically speaking, could those problems be solved by over-filtering and an aggressive water change schedule? I'm not looking to overstock---sounds like too much work!---just curious.

I'm not sure how well filtration works on the unmeasurables I spoke of. I overfilter all of my tanks, but still am religous about my weekly waterchanges. Thanks for the props :)
 
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