Long-distance transport: encapsulated microalgae against ammonia in the bag
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
Ammonia excreted by the fish themselves is the main factor limiting how long a sealed bag transport can last — our travel and safety section covers the other angles. A study by Guerra, Pizarro, Panduro and Castro, published in 2026 in the journal Fishes, tested an unusual way to delay this problem on long trips: capsules of Amazonian microalgae.
Contents · 4 sections
Fifteen days of simulated transport, four microalgae tested
The authors encapsulated four different Amazonian microalgae in calcium alginate — Ankistrodesmus, Chlorella, Scenedesmus and Synechococcus — then added them to the transport water of female guppies (Poecilia reticulata) kept under conditions simulating a 15-day trip, against a control group given an empty capsule.
A striking gap in survival
The result is stark: with Ankistrodesmus and Scenedesmus capsules, survival reached 97.8%, and average ammonia stayed capped at 0.036 and 0.047 mg/L respectively. The empty-capsule control group did not exceed 6.7% survival over the same period. The microalgae consume the ammonia excreted by the fish as it accumulates, instead of letting it build up the way a classic sealed bag does.
What this changes in practice, and what it doesn't
The study concerns guppies and a transport duration far longer than a typical pet-store-to-home trip — it targets long-distance shipping or breeder transports above all. For a trip of a few hours, the usual precautions remain sufficient: our article on how many fish per bag and the one on the pH drop in the bag cover those common cases. The microalgae approach becomes relevant once a trip runs past 24 to 48 hours, a case also covered from a different angle in our piece on adding salt to transport water, another way to limit stress over time.
- 97.8% survival at 15 days with Ankistrodesmus or Scenedesmus capsules.
- Only 6.7% survival for the control group with no microalgae.
- Ammonia capped at 0.036-0.047 mg/L with the best strains tested.
- Study targeted at long transports (breeding, long-distance shipping), not the typical pet-store-to-home trip.
This approach remains experimental and is not (yet) an off-the-shelf consumer product — but it points to a concrete direction for anyone shipping fish over several days: look for an additive that consumes ammonia rather than a simple temporary chemical neutraliser.
Frequently asked questions
Can hobbyist microalgae products be used for an ordinary transport?
The study tests specific lab strains, not a commercial product available to hobbyists. For a trip of a few hours, classic methods (a properly sized bag, stable temperature) remain the reference.
Why is ammonia so dangerous in a sealed bag?
With no water changes or filtration, it builds up continuously and turns toxic at concentrations far below what a filtered aquarium tolerates.
Is 97.8% survival at 15 days generalisable to other fish?
The study specifically covers female guppies. The principle — capturing ammonia continuously rather than neutralising it once — is transferable, but the exact figures may not be to another species.
In our shop, for this use: Programmable automatic aquarium fish feeder (€32.90) · 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.
