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Guides › Adding new fish and shrimp: acclimation and quarantine

Adding new fish and shrimp: acclimation and quarantine

1 min read · Last updated October 16, 2026

How do you acclimate the animal you brought home from the store to your aquarium? Why does quarantine save lives? Safe introduction, step by step.

A new animal brings two risks: water parameter shock and disease. Proper acclimation prevents the first, and quarantine prevents the second.

When buying

  • If there are dead or sick-looking fish in a tank, do not buy from that tank.
  • Avoid individuals with clamped fins, that stay apart from the school, gasp at the surface, or have white spots or cottony patches on their body.
  • Ask the store to hold fish that have just arrived for a few days; losses from transport stress are highest during this period.
  • On the way home, keep the bag in the dark and at a steady temperature.

Acclimation: the floating method (for fish)

  1. Turn off the lights; darkness reduces stress.
  2. Float the closed bag in the aquarium for 15–20 minutes so the temperature equalizes.
  3. Open the bag and every 5 minutes slowly add aquarium water equal to the volume in the bag (3–4 times).
  4. Catch the fish with a net and release it into the aquarium. Do not pour the store water into the aquarium.

The drip method (for shrimp and sensitive species)

Shrimp are very sensitive to sudden change. Transfer the animals together with their water into a clean container and use airline tubing to drip water from the aquarium at 1–2 drops per second. When the water in the container has tripled within 1–2 hours, move the shrimp into the aquarium.

Quarantine: why and how?

Ich (white spot), velvet, neon tetra disease and internal parasites usually enter an aquarium with a newly arrived animal. A quarantine tank prevents this:

  • A simple 20–40 liter tank, a heater and a cycled sponge filter (a sponge kept in the main aquarium is ideal).
  • Observe new fish here for 2 weeks, and high-risk species such as discus and dwarf gourami for 4 weeks.
  • During this time, watch appetite, feces, swimming and skin condition. If there are no problems, move them to the main aquarium.

The first days

  • Do not feed on the first day, or feed very little.
  • New fish may hide and look pale; this improves within 1–2 days.
  • If you have registered your aquarium on the site, add a "New livestock" event to your log; it makes it easier to understand the cause of a possible loss later on.