One of the more contentious topics in fish-keeping is how to acclimate your newly purchased fish for the tank.

The method I prefer for both freshwater and marine fish is drip acclimation. Note that there are a few caveats to this method; if the fish have spent many hours in a shipping bag it is not advisable. As ammonia toxicity decreases with pH it shouldn’t be used because the pH will rapidly climb when the bag is open and the water mixes. This is likely harm the fish as the toxicity of the ammonia spikes.

Drip acclimation can be done as elegantly or as simply as you care to do it. The simplest method uses ¼" tubing and a black metal paperclip. The paperclip is used to crimp the tubing and reduce flow.

Or you can use the same tubing with a suction cup to hold the tubing in place, and a valve to adjust flow. For the more ambitious you can even float the acclimation container in the tank and use a pump for delivery. This will speed up the temperature equalization, though not strictly necessary as the ingress of water from the display tank will do the same.

The use of a valve allows for finer control of drip speed than the metal clip method of crimping the tubing. It is inexpensive to purchase valves intended for use in sprinkler drip systems for the local hardware store as well.

Quite simply drip acclimation is the process of slowly adding water from the tank to the container holding the livestock and the shipping water. This process lets the livestock gradually adjust to the difference between the two. There are always slight differences in mineral content, pH and nitrates as well as the presence of trace materials between two tanks.

I prefer to run my acclimation at roughly a drop per second. Once I’ve doubled the amount of water I’ll scoop out a cupful and continue the process. I’ll spend up to an hour with fragile species, but with hardier fish such as Blue/Green Chromis I’ll run the drip for 30 minutes.

Once the time frame allotted has passed I then net the fish from the container and evert the net into the water. It is advisable to not empty the shipping water into your system as you can introduce undesirable hitchhikers that way. In a marine tank you could conceivably introduce aiptasia or mojano anemones via small free floating juveniles.

With a saltwater system a further step is required if you don’t have a quarantine tank. I strongly recommend using a 4 to 6 week quarantine, but as this is an expensive hobby your resources may not stretch that far.

The final step for a non-quarantine marine system is a freshwater dip. This s a topic worthy of it’s own post so will have to wait until I have some new livestock to demonstrate with.