aggressive mandarin delema

[lizardlady58]

I have three green spotted mandarins-two of which are females and one is a male (I am going by the dorsal fin). My captive bred mandarin which I believe is a female becomes very aggressive towards any introduced mandarins,they lock jaws and she constantly displays to the male or female which makes me wonder if maybe the dorsal fin isn't a reliable indicator of sex. Right now they are all in separate tanks. I put a video up on you tube if anyone would like to see the behavior. Is this agressive behavior normal for a female or is the fish maybe a male and if so, how do I introduce a tankmate without ending up with an injured fish? .

 

[novahobbies]

It's possible that your aggressive fish is a juvenile male. IIRC the captive bred mandarins are being marketed out at a relatively young age, so the dorsal spike that we usually consider an indicator may not have grown in yet. In the wild I know males will fight over territory, etc. (Discovery channel had a great reef program that showed Mandarins n the wild...was too cute!) How big is this tank again? 3 Mandarins is a lot even for large tanks!

 

[btldreef]

It's probably a young male.
I've seen two females fight to the death though. Mandarins are fairly territorial unless they're a mated pair.

 

[lizardlady58]

The aggressive mandarin is a captive bred youngster so it probably is a young male. I removed the introduced male shortly after I noticed this behavior. Each mandarin is in it's own twenty five gallon tank connected to a seventy five gallon system at the moment. They get fed copepods, live brine shrimp, bloodworms, etc. They are accompanied by one pair of orchid dottybacks in their tanks. I will move the wild caught mandarins to a fifty gallon reef tank that has lots of copepods and "critters" when i see that they are doing okay.