Overview
Freshwater aquarium plants are essential for a low maintenance tank. I have a 15 gallon tank with 12 celestial pearl danios, 6 amano shrimp, 5 otocinclus, and 4 guppies and nitrate levels never move into the detectable range with my API test kit. My plants grow fast to remove the nitrates and below are the things you'll need to make that happen
- Fast growing pant species, most of them are but some like Anubis aren't.
- A good soil substrate, I use commercial Fluval stratum.
- Water column fertilizers, usually just potassium + trace elements since those aren't found in the fish food or poop
- Strong lights
- Options but recommended to have CO2 injection, it will make a noticeable difference.
The downside is that you will need to change all the soil after ~2 years once it's depleted, or sooner. Whenever you notice plant growth slowing down. This is a massive pain and you basically need a second tank to hold everything while you make the change and let the water settle. But overall it's very worth it.
Also, remember to underfeed instead of overfeed. It's better to leave them a week without food than to overfeed them once. Fish can go way longer than you think without eating, even for small fish like guppies they can go a week without food.
Warning - Pests
Watch out for pests that hitch hike on plants. I've gotten plants from reputable pet stores and then 5 months later see a dragonfly nymph sneaking around trying to eat my shrimp.
A common practice is to dunk your plants in a hydrogen peroxide and water bath and then rinse them off before putting them in your aquarium. That kills off most things without hurting your plants