Can freshwater fish be moved around to different tanks regularly or is it too stressful?

Moving freshwater fish around to different tanks regularly can indeed be stressful for them, and should be avoided if possible. Here's why:

1. Acclimation Stress: Every time a fish is moved to a new tank, it needs to acclimate to the different water parameters (temperature, pH, hardness, etc.) of the new environment. This process can be stressful, as it requires the fish to make physiological adjustments to survive in the new conditions.

2. Transportation Shock: The physical process of capturing and transporting fish can also be stressful. Fish can become injured during the catching process, and the jostling and movement during transport can further add to their stress.

3. Territorial Behavior: Freshwater fish often establish territories within their tanks. Moving a fish to a new tank where another fish has established its territory can result in aggression and territorial disputes, which can further increase stress levels.

4. Disruption of Social Structures: Some fish species live in social groups or have established hierarchies within the tank. Moving one fish out of a social group can disrupt the dynamics and social structure, leading to increased stress for all the fish involved.

5. Disease Transmission: Moving fish between tanks can increase the risk of disease transmission, especially if the new tank already contains sick or stressed fish. This can further compound the stress experienced by the introduced fish.

If absolutely necessary to move a fish, it's important to minimize the stress involved:

- Acclimate the fish slowly to the new water conditions by gradually mixing small amounts of the new tank water with the old tank water over the course of several hours.

- Handle the fish gently and carefully to avoid causing injuries during capture and transportation.

- Introduce the fish to the new tank gradually, perhaps by placing it in a floating container for a while to allow it to observe its new environment before releasing it.

- Consider housing aggressive fish in separate tanks to avoid conflicts.

- Quarantine any new fish before introducing them to the main tank to reduce the risk of disease transmission.

In summary, while it is possible to move freshwater fish between tanks, it should be done infrequently and only when necessary to minimize stress and potential health risks to the fish.