Sexing spotted mandarins

Chem1586 · May 2, 2020

Anyone out there have experience pairing mandarins? I just added what I believe is a male to what I believe is a female (she is looking really fat like she might lay eggs soon, and she’s been out in the open almost as if she’s looking for a mate).

Does it look like I have the genders correct? The larger one (female?) has been in my tank for about 6 months. The smaller one (male?) I just picked up at the LFS. I’ve included the best pics I can get of their dorsal fins. Does it look like the female is ready to lay eggs?

She was aggressive with him at first but they seem to be getting along a lot better already.

ThRoewer · May 2, 2020

Males have an elongated first dorsal spine, females don't have that.
But sexing is not the whole deal as females usually only accept males that are a good deal larger than they are. Males that are deemed too small (= inferior) may get beaten up or even killed.

Chem1586 · May 2, 2020

That’s what I’m worried about. I read that after I added him unfortunately... she bit him at first, but today they have been swimming around together a bit without any aggression.

Sosuke · May 2, 2020

Chem1586 said:
Anyone out there have experience pairing mandarins? I just added what I believe is a male to what I believe is a female (she is looking really fat like she might lay eggs soon, and she’s been out in the open almost as if she’s looking for a mate).

Does it look like I have the genders correct? The larger one (female?) has been in my tank for about 6 months. The smaller one (male?) I just picked up at the LFS. I’ve included the best pics I can get of their dorsal fins. Does it look like the female is ready to lay eggs?

She was aggressive with him at first but they seem to be getting along a lot better already.

They don't lay eggs they breed in the water column so raising the babies might be too tough to do if thats what you were hoping for, not that it can't be done but it is very tough. About the pairing process females need to be added first and the male has to be either the same size or large IME. I would try to get him out before he gets killed if possible

ThRoewer · May 2, 2020

Chem1586 said:
That’s what I’m worried about. I read that after I added him unfortunately... she bit him at first, but today they have been swimming around together a bit without any aggression.

Keep an eye on them. They may get along.
I had a pair of mandarins where male and female were the same size and the female was quite rough on the male. But he survived it and outgrew her fast. Once he was a bit larger than her they got along and started spawning.
In your case it looks like the female is gravid and may just accept him so she can get rid of her eggs.

Chem1586 · May 3, 2020

They have been swimming around most of the day together without aggression, both keeping an eye on each other and foraging for food on the rocks.

I wasn’t specifically planning on trying to raise the babies, not ready to culture a food source for them or setup a hatchery, just wanted to get two paired up to watch the relationship. It has been really cool watching them swim around together today.

Chem1586 · May 4, 2020

2nd night in the tank and they’re doing their thing. Although it seems like the little guy still has a lot to learn. And he is still thin from the LFS so he kept taking “snack” breaks! It was really fun to watch!