Long-time fishkeepers will know that live plants are more than tank decorations or a fun indoor gardening opportunity. They can make a real difference in the health of our systems and fish by helping to keep the water quality stable, providing a surface for biofilm to grow on, and creating a more natural environment. A new study suggests that thanks to these characteristics, Betta fish (Betta splendens) kept in tanks with live plants show higher activity levels and fewer signs of stress.
The researchers who carried out this aquarium plant experiment, which was published in January of this year, were particularly curious about whether live plants can improve the lives of Betta fish kept in tiny, unfiltered containers at aquarium and pet stores. Tanks of just two liters (about 0.5 gallons) were used to test their hypothesis that live plants help keep the water parameters in an acceptable range and reduce signs of stress in the fish.
The experiment was divided into four groups. Three were planted with dwarf sag (Sagittaria subulata), scarlet temple (Alternanthera reineckii), and Asian watermeal (Wolffia globosa), respectively. The control group didn’t contain any plants. The results showed that aquatic plants can reduce the amount of ammonia and helped foster a more diverse community of microbes, many of which also have a positive effect on water quality.
Aside from the water parameters, attention was also paid to the behavior of the tanks’ inhabitants. Signs of stress were measured here as the number of times the fish darts to the surface to breathe every five minutes, plus the amount of time it spends swimming. Thanks to the improved water quality, Bettas whose tanks contained plants darted to the surface less frequently. They also spent less time listlessly hanging around the bottom of their containers, a clear sign of stress you might have seen in pet store fish.
Beginning aquarists often start out wary of trying live plants, or move away from them after their first tries are met with failure (not always by their own hand, either: how are you supposed to know you need to take your new greenery out of its little plastic jail before planting it, or that some of the plants sold for the aquarium aren’t actually aquatic and will die underwater?).
Fake alternatives can be more than just eyesores. Using them means keeping your aquarium stable will genuinely be more challenging, which is the last thing a starry-eyed first-timer needs. Some hard plastic (rather than silk) plants are even known to tear the long fins of species like Betta fish and guppies, which can lead to infection.
Of course, the results of this latest study don’t translate 1:1 to our tanks. Here at FantaSEA Aquariums, in any case, we recommend a minimum water volume of five gallons (rather than zero point five) for a Betta fish. We also recommend using a filter to cycle your Betta tank before acquiring your finned pet, meaning the baseline ammonia level will already be zero — as it should be if you want a healthy fish. But that’s not the point.
More than anything, this latest experiment — along with a growing body of work specifically investigating ornamental fish and tanks — is a good reminder that aquarium plants aren’t just for aesthetics or bragging rights (although they do help with those, too). Combined with previous research, like on whether a barren Betta tank leads to stress (it does), this paper makes it clear that our tiny, feisty finned friends need enrichment and clean water like any other animal. The same goes for all aquarium fish.
What are you waiting for? If you haven’t, go forth and plant. You might find your thumb is greener than you think, and we’re here to help if you run into trouble. 🌱
Xu, Y., Li, L., Chen, Y., Zhang, Y., Niu, T., Huang, P., & Chai, L. (2026). Effects of Aquatic Plants on Water Quality, Microbial Community, and Fish Behaviors in Newly Established Betta Aquaria. Animals, 16(2), 247.
