Do Anubias need fertilizing and substrate at all in strongly filtered tank?

[EggShappedFish]

I am planning on only having Anubias in my tank, as goldfish tend to consider anything else, as "challenge-food".

My question is, do I need to fertilize them, when I actively try to keep nitrates, nitrites and phosphates low, with active filtration and regular water changes? Will this allow Anubias to grow at all?

Also, will they cope, with no or very little substrate?

[Tony s]

They can be glued directly onto any object in your tank, so no substrate required. They will need a minimum amount of nitrate, usually around 10 will work as they are very slow growers. Other micros will come from the new minerals at water changes. Unless you’re going to use RO. Then you would need to reminerize it.

You could use some of the very tall types and create sort of an Anubias forest as it were. Would look very cool glued to a large piece of driftwood.

[Tony s]

For a faster plant, you could try floating some hornwort. It may grow faster than they eat it. Or even duckweed at the surface. As long as you leave open ares for gas exchange. Duckweed would provide a food source as well. 

[EggShappedFish]

On 3/6/2024 at 12:44 PM, Tony s said:

They can be glued directly onto any object in your tank, so no substrate required. They will need a minimum amount of nitrate, usually around 10 will work as they are very slow growers. Other micros will come from the new minerals at water changes. Unless you’re going to use RO. Then you would need to reminerize it.

You could use some of the very tall types and create sort of an Anubias forest as it were. Would look very cool glued to a large piece of driftwood.

Very good thanks.

Although I don't know the rate at which nitrates accumulate, I do water changes at approximately 20 So I would assume that it averages 10.
I will look into the tall types, but I mostly use them to add green colours, because the fish get stuck in them if I use too many plants. I was mostly concerned if they would get enough nutrients from the roots if the water was low in nutrients

 

On 3/6/2024 at 12:51 PM, Tony s said:

For a faster plant, you could try floating some hornwort. It may grow faster than they eat it. Or even duckweed at the surface. As long as you leave open ares for gas exchange. Duckweed would provide a food source as well. 

Ah it's interesting that you mention those. I have tried hornwort, but it kept melting away for me. Duckweed has no chance at all in my tank. It gets eaten within a few hours! I did try some Red Root Floater that they didn't eat, but they also melted away. I do have some fairly strong surface agitation though, so this may be part of the problem

[Tony s]

They would be great at 20. They should even slow down the rate at which you need to do changes. As long as they have a constant source of food. They are strictly water column feeders, so depend on having the nitrates

The roots are mainly used as a holdfast for grabbing onto objects they have been glued to.  They can even be grown as floaters, but they lose their normal structure that way. And grow In every direction at once 

[Tony s]

Hornwort will very quickly use up all available nitrogen from a low nitrogen tank. It can actually starve and melt away. Which is not good as its leaves will shed like dried Christmas tree needles and get everywhere.

[EggShappedFish]

On 3/6/2024 at 1:08 PM, Tony s said:

Which is not good as its leaves will shed like dried Christmas tree needles and get everywhere

This is exactly what it did yeah!
I assume it eventually generates its own nitrogen this way, in a tank, but it was counterproductive (and ugly) for me. Also I have seen goldfish get hornwort stuck in their mouth. It has pretty rough leaves when you touch it actually!

[Tony s]

Have never seen anything try to eat it before, but goldfish gonna be goldfish. usually makes a good hiding place for small fish and fry. Looks a bit unkempt, but I like the look.