I can see one of them is a sword, the others are Anubias?
Anyways, if you bought emersed plants, they would go through an adjustment period before they start to thrive. If they had the right lighting, nutrients and like Caliban said, CO2, they should come back nice and healthy.
1. What kind of light do you have and how long do you run it for? What you have are low light plants. I would suggest running the light no more than 8 hrs with a 4 hr siesta period. For example, 8 am - 12 pm on, 12-4 off, 4-8 on. This siesta period helps increase the amount of dissolved co2 in the water. Plants use co2 every time the light is on.
2. You don't have a special plant substrate which means you need to use root tabs especially for plants that have roots under the substrate.
3. Liquid CO2 would help the plants stay healthy over the long run.
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