Vallisneria Dying

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Aquarium Advice Apprentice
Sep 19, 2022

I have a 250l community tank. I recently added some Vallisneria plants and they appear to be dying. The top half are going brown and Wilty. They are planted in gravel and I added some Seachem root tabs when I put the plants in but that is it. There are 4 plants and I have just 6 neon tetras as it’s a relatively new tank and I’m adding fish gradually. Any ideas why they are doing so badly? Do I need to add another supplement? If so any suggestions?
Can you post a photo?

What supplements are you currently dosing?

Could just be plant melt which is normal when plants are first introduced to an aquarium.
Not using any supplements as such just Seachem Flourish root tabs. Photo to follow
Commercially grown plants are cultivated “emersed” rather than “submerged”. This way the plants can easily get their carbon requirement from atmospheric CO2. They can be grown quicker which makes the operation much more commercially viable. You take that plant, put it in your aquarium, cut off its source of CO2 and the plant goes into survival mode. It starts to use up its stored carbon and the leafs melt. You may lose all your original growth to melt but new leafs will have a structure more suited to its new environment and get its carbon from the water. Plant melt is a normal stage in aquarium plant growth. To judge the health of a plant look for new growth rather than what might be happening to the original growth, and judge it over extended periods of time.

Remove dead and dying growth so the plant can concentrate its resources on new growth rather than trying to support dying leafs.

Plants need a level of nitrogen and in aquariums they typically get this from nitrate. From one of your previous posts your plan was to stock lightly and gradually increase the number of fish. So you may be low on this essential nutrient, but as you increase the number of fish your nitrate level should increase.

Your plants should benefit from an all in one liquid fertiliser and root tabs in the substrate around the plant.
You are right, I just have 6 Neon Tetra at the moment. By all in 1 fertiliser, do you mean a product such as Seachem Flourish Comprehensive supplement?
I use seachem flourish. This will cover the needs for low demand plants like vals. It doesnt include much nitrate or phosphate which plants need, but these will normally come from your fish.

If you need something with nitrate and phosphate that will depend on where you located. NA Thrive is a good one to go for if you are US based. TNC Complete here in UK. Tropica does a nitrate containing fertiser as well but i find tropica supplements expensive. But see where your nitrate levels are when you are more fully stocked before looking at these.
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Vallis is one plant that can't be grown emersed and only lives underwater. When it dies off like this, it is usually lack of light of sudden change in water chemistry (pH or GH).

Make sure you have lots of light (up to 16 hours a day), and use an iron based aquarium plant fertiliser. I used Sera Florena but there are other brands too.


You need a picture on the back of the tank to make the fish feel more secure. You can buy aquarium backings form any pet shop or online. You can also use coloured card, newspaper or a plastic bin liner. Just tape them to the outside on the back of the tank.

The white gravel will cause your fish to stress and a darker gravel (black or brown) is better. If you don't want to change the substrate, add some floating plants like Water Sprite (Ceratopteris thallictroides/ cornuta) and it will shade the substrate, reducing the glare.
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