Artificial plants in the aquarium: a real benefit for fish, or just less room to swim?
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
"Add plants, it reduces stress" comes up so often among aquarium keepers that it sounds like common sense. A research team decided to test that assumption over the long term rather than over a few days, in a species already extensively studied in the lab: zebrafish. Our enrichment ideas by animal are gathered in the fish toys and enrichment section.
Contents · 6 sections
One year of tracking, six zebrafish lines
Krachni, Busch, Brakus, Schumann, Wilzopolski and Ohnesorge published a study in 2026 in PLOS One comparing, over one year and six different zebrafish lines, rearing tanks fitted with artificial plants against bare control tanks with no decor at all. The researchers started from a specific hypothesis: would artificial plants reduce anxiety and stress enough to improve reproduction and egg laying?
No measured benefit, either on stress or on reproduction
Over the year-long tracking period, growth, stress markers, and reproduction and spawning outcomes showed no significant difference between the planted and bare tanks, whether the decor was placed in the everyday home tank or only in the mating tank. The authors offer a simple explanation: if baseline stress is already low under well-run standard husbandry conditions, there is not much left to reduce further with decor.
The one effect that did show up: less room to swim
The study's most concrete finding is not a benefit but a cost: artificial plants take up volume that is then no longer available for swimming. For zebrafish, an active open-water swimmer rather than a burrowing or hiding species, that is not a trivial detail in a tank of limited size.
What this does not overturn
This finding does not contradict studies showing that structured decor reduces aggression or cushions an actively imposed stressor, as our guide on tank enrichment and chronic stress covers: those protocols imposed a series of active disturbances (water level changes, temporary space restriction) to measure a protective effect, while Krachni and colleagues simply compared two stable housing conditions over time, with no added stress. The two results measure different things and do not cancel each other out.
What this means in practice
A completely bare tank is not automatically a case of neglect if the fish shows no sign of distress in it: decor remains largely a matter of aesthetics and personal preference for many calm shoaling species. For an already cramped tank, it makes more sense to keep a minimum of structure than to keep adding elements that eat into swimming space with no demonstrated benefit beyond a certain point.
Frequently asked questions
Should artificial plants be removed from a tank after this study?
No: the study shows no downside to welfare, only an absence of measured benefit and reduced swimming space. In a spacious tank, that has no practical consequence.
Does this study apply to every fish species?
It specifically covers zebrafish under laboratory husbandry conditions; other species, territorial cichlids in particular, show a different behavioural response to decor, as our guide on cichlids and enrichment details.
In our shop, for this use: Tall artificial aquarium plant, 45 to 49 cm, weighted base (€23.90) · the whole shop
This guide is part of Planète Pets’s Fishkeeping universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.