Changing my substrate

I would like to change the substrate in my up and running 5.5 gallon Betta tank. I am currently in week two of a fish in cycle. I am thinking of changing the substrate next month to something I can plant real plants in. I would like new more natural rock and wood décor too.

My question is: Once I remove the decorations and fake plants, can I change my substrate without draining all the water in the tank or do I have basically empty the entire tank and start over? I would ideally like a layer of soil underneath a layer of dark gravel. I don't mind totally redoing the tank but it's the health of my fish I am most concerned about.

I know it's probably a dumb question but I haven't owned an aquarium in over 40 years so any help would be appreciated.

Plants will grow in almost any substrate, from sand to fine gravel. Some will be fine in pea gravel, but any gravel larger than this may not work well. What substrate do you have now?

There is a misconception that soil under sand/gravel is needed, but this is minimally beneficial and usually problematic for the first six months or so. High ammonia due to the organic matter rapidly breaking down (ironically this is the only benefit from soil as this action produces CO2 but it is not permanent) can kill fish, which is why many soil-substrate authors advise a six month dry start before fish are added. I personally wouldn't bother; I have had low-tech natural planted tanks for 30 years with either fine gravel or play sand substrates.

As for changing the substrate if you do, then yes, the best method is to remove the fish to a temporary tank, remove all décor, drain, and take out all the substrate. Then start afresh. If you keep the filter running without cleaning (I always set this in the temporary tank with the fish and floating plants) it will retain the nitrifying bacteria and certainly more than sufficient for a single Betta. And the plants will take up any ammonia anyway.

Thanks for the suggestions and info. Right now the tank has river rock substrate which I am not crazy about. Yes after doing some more research on soil the high ammonia problem is a concern so I won't be doing that with this tank. I will just go with a smaller dark gravel that can hold plants. That will be much easier too.

I do have another 2.5 gallon tank my Betta can hang out in while I re-do his 5.5 gallon tank.

I have plants growing in bog standard aquarium gravel. If it bothers you can use root tabs to allow nutrients to absorb into the gravel but my plants are doing just fine on their own.

TallPaul said:

I have plants growing in bog standard aquarium gravel. If it bothers you can use root tabs to allow nutrients to absorb into the gravel but my plants are doing just fine on their own.

Click to expand...

That sounds basically what I want. I am not really interested in adding root tabs. Do you add fertilizer of any kind?

Eventually I do want to set up another fully planted nano tank using the Walstad method taking time to do it properly. Maybe for shrimp only. For now with my Betta tank I will keep it simple but Betta friendly.

Phil Fish said:

That sounds basically what I want. I am not really interested in adding root tabs. Do you add fertilizer of any kind?

Eventually I do want to set up another fully planted nano tank using the Walstad method taking time to do it properly. Maybe for shrimp only. For now with my Betta tank I will keep it simple but Betta friendly.

Click to expand...

Substrate tabs are the best plant fertilizer for an aquarium because they do not leech minerals/nutrients into the water column. At least Seachem's Flourish Tabs do not do this. Liquid fertilizers also work for plants, but here you can have algae problems, plus the fertilizers get inside fish and it is always best to keep this to a minimum. For larger plants, substrate tabs are ideal.

However, having said that, in a small tank like this one you are not going to have large plants that will benefit from substrate fertilizer, though you could still cut the tabs apart and use them.

Ok so what you're saying is I can get by without liquid fertilizer or root tabs due to the size of my tank? Would the plants live off the fertilizer (poop) provided by my Betta or does he not provide enough?

Phil Fish said:

Ok so what you're saying is I can get by without liquid fertilizer or root tabs due to the size of my tank? Would the plants live off the fertilizer (poop) provided by my Betta or does he not provide enough?

Click to expand...

Maybe. Each tank is different. A single Betta is not going to produce much in the way of nutrients (the decomposing fish poop is the prime nutrient), and I also do not know the lighting and this drives photosynthesis so without nutrients, too much or too little light, plants may struggle and algae take hold. If you could give me an idea of the intended plant species, and the lighting, I might be able to pin this down. Some plants need less of light/nutrients (mosses, Java Fern, etc), others much more.

My tank has quite bright LED lights built into the lid. It's the Top Fin Essentials 5.5 gallon starter kit. The lights are so bright they cause reflections that bother my Betta so I leave them off most of the time. He's much happier too. That's one of the reasons I want some real plants. To give him a more natural environment and give some shade.

I am looking at Java fern, Amazon Sword, water sprite, anubias and maybe dwarf grass if possible?

If bright light is an issue now, you can get some floating plants. The tiny ones like duckweed and Salvinia are not what you want here, but the more substantial plants like Water Sprite (absolutely the best no question), or Water Lettuce or Frogbit if you can't get WS. A good cover of the entire surface should solve this issue.

That means less light getting to the lower level, so plants rooted in the substrate will need to be moderate to low light requiring. Java Fern is ideal, and Anubias. The carpet plants like dwarf grass are not easy to grow at the best of times but bright lighting is needed so I would forget those. Swords will get quite large for this small tank, but the chain swords should work very well. I have these thriving in any tank I add them to. Helanthium tenellum (previously considered Echinodorus tenellus) or the very similar but just slightly larger leaf H. bolivianum.

With the above, you will likely need a comprehensive fertilizer, like Seachem's Flourish Comprehensive Supplement for the Planted Aquarium. I use this, sparingly, but another basically the same is Brightwell Aquatics' FlorinMulti.

Byron said:

If bright light is an issue now, you can get some floating plants. The tiny ones like duckweed and Salvinia are not what you want here, but the more substantial plants like Water Sprite (absolutely the best no question), or Water Lettuce or Frogbit if you can't get WS. A good cover of the entire surface should solve this issue.

That means less light getting to the lower level, so plants rooted in the substrate will need to be moderate to low light requiring. Java Fern is ideal, and Anubias. The carpet plants like dwarf grass are not easy to grow at the best of times but bright lighting is needed so I would forget those. Swords will get quite large for this small tank, but the chain swords should work very well. I have these thriving in any tank I add them to. Helanthium tenellum (previously considered Echinodorus tenellus) or the very similar but just slightly larger leaf H. bolivianum.

With the above, you will likely need a comprehensive fertilizer, like Seachem's Flourish Comprehensive Supplement for the Planted Aquarium. I use this, sparingly, but another basically the same is Brightwell Aquatics' FlorinMulti.

Click to expand...

Perfect! I will make a list of those plants and fertilizer and try them out once I decide on how I want the tank to look. I know I need taller plants along the back and sides. Even with his tank light dimmed with a piece of off white paper taped over it my Betta still plays tag with his reflection. He's a little warrior...lol. If I have his light on full he flares at everything! At least with it dimmed he just does "security" checks of his environment. I think with a thickly planted tank he'll feel more secure.

Thanks so much for the advice!

Hi, sorry I have been away. I will update you on my plants.

I have elected to remove my floating plants as they propagated rapidly and became a nuisance when doing maintenance in the tank. They have done their job in helping with the cycling process but now that I have 2 cycled tanks with good plant growth I took them out.

My first tank uses JBL Manado substrate, it is a sort of clay coloured fine gravel that is supposed to be beneficial for plant growth. In reality it is snake oil. There are no nutrients in it and I would be better off using regular sand or gravel because this stuff is so lightweight that it constantly floats away and plants take a long time to get rooted.

My second tank is the betta tank, it uses a standard dark mix gravel (black, brown, grey colours). I have crypts and hygrophilia planted and they are flourishing.

I had originally added Tropica liquid fertiliser but it is unnecessary as they are flourishing on their own with whatever is already in the water.

I will add that I do use Easy Carbo, it's a gluteraldehyde plant "product". I use this to fight algae (I believe it may be BBA but it's brown and grows on the glass and wood).

I scrubbed the wood, during a water change, with a toothbrush and Easy Carbo and it has eliminated the algae on the wood.

I would recommend just watching your plants before you decide to do anything like add CO2 or additional ferts. Doing it again I would have just used root tabs for the crypts as the hygrophilia will grow like a rocket if I had poured concrete into the tank.

This is Spike in his planted tank. The hygrophilia are all cuttings from the previous tank and have grown incredibly quickly without any interference from me

These are my Embers in their tank. You may notice some "melt" on the new crypts. That is common as they are grown out of water and need to adjust to their new environment.

The hygrophilia at the back had already been trimmed for the betta tank and is at the surface again