Questions about Zoramia leptacanthus (Longspine Cardinalfish) pairing.

[wantacookie]

It seems that two, out of a small group of six, of these fish have began to prefer spending their time together on the opposite side of the tank as the rest of the group. The pair will seek the security of the group when another species of fish swims by and disrupts them. Soon after, they are together in their spot. The pair do a lot of gentle rubbing and nudging when alone.

There's never been any noticeable aggression from the group that would cause the two fish to separate. The two that have paired are the largest two of the group. I cannot see a difference between the two, other than size.

If the rest of the group were removed from the system, would it have a negative or positive effect on the possibility of the two fish pairing up?

Also, I'm curious to know how to determine the sex of this fish.

Thanks for any help!

 

[snorvich]

Removing the remaining fish would have no effect.

 

[mrwilson]

Interesting. I've had a small shoal of seven for a short time, and have yet to see any obvious pairing behavior. What sizes, exactly, are the pair and the remaining cardinals?

 

[wantacookie]

The pair are both over 2", with the larger one being a smidgen bigger. I originally purchased 3 at a LFS from a group of maybe 10 to 15. The third one is around 2". After I had those guys for around two weeks, I ordered some extra CUC items from liveaquaria and decided to tag on 4 more of these fish. One died during shipping, leaving me with six in all. The fish I received from liveaquaria were much smaller. The largest coming in around 1.5". Smallest, about an inch. Immediately, they all got along well.

They've been together happily for almost 2 months getting fat on cyclopeeze, PE mysis, NLS pellets, and anything else I throw in there.

I've read that the males have larger mouths than the females. However, they all have big mouths in my opinion. Any other way to tell male from female?

 

[velvetelvis]

I had a couple pairs for a while before giving them to a friend with a bigger system who wants to breed them. The differences between the sexes were subtle. The females were larger and fatter, and the males had a slightly more elongated dorsal spine. But really, the only time I was sure was when the males were holding eggs.

The good thing is that they're such peaceful little fish, you won't have to worry about aggression while you try to get them to pair up. You can also buy them as pairs off DD, usually from ORA or Sustainable Aquatics.

 

[wantacookie]

But really, the only time I was sure was when the males were holding eggs.

I think that's what it might come to for me, hopefully. Thanks for the tips!

 

[wantacookie]

Got egg mass in male!!! Trying to get clear pics but camera sucks. Will update.