When adding new fish, there are three factors we need to consider:

  1. What fish are already in the tank and what other fish are we adding
  2. Making sure the fish are acclimated
  3. Whether we need quarantine the fish How best to acclimate them do we trust the source where we acquired the fish

Compatibility

This is a complex topic that we addressed in another section.  However, there are additional issues we need to consider when adding new fish to the tank.  Healthy Aquatics also provides consulting and education services on this topic.  

Quarantine?

Unless you acquired your fish from a trusted source, a very well established aquarium or one of the few pet stores with a real quarantine protocol in place, it is wisest to quarantine all fish before introducing them to your display aquarium. This also offers the opportunity to ensure that the fish is eating and to get them used to life in an aquarium.

Some displays have a prophylactic medication (such as copper) running constantly. Other systems, such as tanks with only fish and artificial decorations, can be treated with certain medications (such as the anti-worm drug praziquantel) as needed. Medicating the display tank however is less ideal than quarantining all fish as drugs in the water, both short and long term, can cause unforeseen complications.

Acclimation

Fish must be acclimated to any new system, both quarantine and display. Ideally, they are put in a system which has not been medicated and then treated after 24 hours to allow for minimal variables if something goes wrong; you want to know if it's the water chemistry or the medication.  For coral and invertebrates there are additional considerations.  Before starting acclimation it is wise to add a product which neutralizes ammonia to the acclimation bucket/bag. Products such as amquel and prime should be used as directed but should only be a few drops.  The longer you acclimate the better:

  • 10 drops per second = 1 hour to double water volume, 2 hours acclimation minimum

  • 5 drops per second = 2 hours to double water volume, 4 hours acclimation minimum

  • 1 drop per second = 5 hours to double water volume, 10 hours acclimation minimum

  • Your drip set may make bigger drops so watch carefully and adjust accordingly

  • You don't need to start with a gallon of water. For clownfish for example you can start with a quart of water (¼ gallon) and add 2 drops per second for 2 hours

Nerd note: High ammonia is common in shipping bags and the longer a fish is in a bag, the lower the pH of the bag's water gets. Ammonia is less toxic in low pH ( more is in ammonium form which is non toxic) but as we acclimate and raise the pH...the ammonia can become very toxic, hence using ammonia detoxifiers (keep ammonia as ammonium no what the pH is)