This should be helpful.
Forming pair bonds in clownfish
A how to guide
By: John Hardman
First you need to understand clownfish --- change and how that effects pairing and interaction. Please refer to Knol on sexing clownfish page for further information.
Briefly, clownfish are protandrous hermaphrodites. They are hatched as sexually immature fish. Based on signals from their environment and being physically mature (12-24 months) they will either remain sexually immature, change into a male or change into a male then female. This is a one way trip, sexless to male never to be sexless again and male to female never to be male again.
A clownfish kept by its self will become a female in a short period of time if it is physically mature, in as little as a month.
Second two female clowns will fight. The tell tale sign that you have two females is fighting ending in the two locking their mouths together.
Clownfish pairing techniques:
There are a couple of proven techniques to pair the same species of clownfish. Mixing species of clownfish should be avoided and has very limited long term (multi-year) success (only one case that I know of and could be considered unsuccessful as at least one clownfish was killed by another clownfish in the tank).
Grow out technique:
With this technique two small juvenile clownfish are purchased at the same time and introduced into the tank at the same time. The fish will establish a dominate submissive relationship as they mature and eventually form a pair bond. This technique works the vast majority of the time.
Notes: Since the fish are going to fight and/or chase each other to establish who is the dominate fish and who is the submissive fish, it will often speed the pairing process and reduce fighting and potential damage to the fish by getting one of the two juveniles larger than the other.
This technique should not be applied to Premnas species (maroon) clownfish.
Add a new clownfish to an existing clownfish technique:
With having an existing clownfish in your tank adding a new clownfish to form a pair can be a little harder or in other words more dangerous to the new fish. The technique is basically the same as the grow out technique. You will want to find a small juvenile clownfish and add it to the tank with the existing tank. By getting a small juvenile fish you are not risking possible --- compatibility problems, e.g. two females.
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