Stocking beyond what aqadvisor recommends

[ramtsi]

20 neons, 9 amano shrimps and one honey gourami in a 20 gallon heavily planted tank, all parameters are 0. According to aqadvisor this is 100% of my filtration capacity, and a 91% stocking level. I'm running an internal 100l/h + a sponge filter.
Will it be safe to add 10 ember tetras to the tank?

 

[Aiken Drum]

Aqadvisor probably says something like change 40% of the water per week with your current stock level and after you add in the additional ember tetras to change 50% of the water.

From a purely bioload PoV you can add these extra fish and simply compensate by changing more water. If you are able to control nitrate to a safe level with a 50% weekly water change then thats great.

From an aesthetics PoV 20 small fish in a 20g tanks feels right to me, and 30 small fish would feel crowded. Less can often be more. But thats personal preference and its to you to decide how many fish you want to see.

I would question your water parameters. Even with a heavily planted tank i wouldnt expect it to consume all your nitrate. Perhaps if you have surface plants, terrestrial plants with their roots in the tank water or a high tech set up with fast growing aquatic plants. If you are confident with your testing and you genuinely are seeing zero nitrate over an extended period this could cause nutrient issues for your plants as they need nitrogen which comes from nitrate in an aquarium and you may need a fertiliser that has a good amount of nitrogen in it. Most aquarium fertilisers have practically zero.

I would live with your tank for a little while. See if the nitrate consistently stays low. If so, and you feel you want to see more fish then add some and change a little more water than you are now. If you continue to see low nitrate and see signs of nutrient deficiency in your plants look at an all-in-one plant fertiliser that contains nitrate. Something like NA Thrive if its available in your location. We have TNC Complete here in the UK.

 

[Joe_D]

In a fully cycled tank you will indeed have some nitrates which are not toxic for fish unless it's in really high levels. Besides, plants need some nitrate to flourish.

How high is too high can never be agreed upon. So, if all is all fish are doing fine, do not worry about nitrates too much.

BTW, one of the main reasons we do water changes is to keep the nitrate in check to what one considered an acceptable level in our closed, artificial systems.
In the wild, nature takes care of all of this

 

[Colin_T]

The number of fish that can live in an aquarium varies depending on a variety of things.
What are the tank dimensions (length x width x height)?
A 20 gallon long is better for fish than a 20g high.

How often do you feed the fish?
If you only feed once every couple of days you might be able to hold more fish than if you feed 3 times a day.

How often do you do water changes and how much do you change?
More fish means more waste and the water quality and aquarium will become dirtier faster. To compensate for this you need to do more water changes and gravel cleaning.

Will the new fish get along with the current fish?

Is there sufficient room for them to each have their own personal space?
The fish might all fit in the tank but will there be enough room for them to act naturally and not swim into their neighbours whenever they move. Even neon tetras need their own space and whilst the fish might swim very tightly together when threatened, they need a few inches around them when relaxing. Add more fish and there might not be enough space for each fish, which could result in stress.