Do Physical Characteristics Indicate Sex?

[pufferpuggirl]

I recently moved my small miurus puffer over by my bigger miurus, and with the tanks being side by side, it has been easier for me to compare the two. I've noticed that there is a difference between them, aside from one being bigger and a different colour than the other. Orangey has more distance from eyes to mouth than Biscuit does, and that reminded me of my very first Congo puffers. I was lucky enough to get a sexed pair, male and female. You could see the differences between them as one had a longer snout than the other, and we knew the one was female because she had been laying eggs. Thing is, I've forgotten which is which. I think the longer snout indicates a male, whilst the shorter snout indicates a female.
Unfortunately I lost the sexed pair of miurus because I didn't know anything about IP's back then, and I had fed them live fish that had come right from the LFS and I'm sure they got IP's, and that was the cause of their death. Shame too because I will probably never have a chance like that again. They lived together too, and did not try to kill one another either.
I know that most information says you cannot sex a miurus, but thing is, there's definitely a difference in appearance and I know I had a male and female before who exhibited these same physical differences.

I've taken some photos of both of my miurus to try and show the differences, but they did not come out very good. For one thing, Biscuit would not move, just sat there puffing up a bit, so I don't know if you will be able to see the difference between the two. I believe Orangey (the bigger one) is a male, with a longer snout, and I think Biscuit is a female, with a shorter snout.

Here's some photos of Orangey, the bigger miurus and the one I think could be a male.







And here's some of Biscuit, the smaller one, and the one I've had the longest -- sorry I know these aren't very good photos.

[Pufferpunk]

He does look like a lil buttered biscuit!

[L!$A]

Oh man Suzanne! Looking at your congo's makes me want one even more!!!!!

[pufferpuggirl]

He does look like a lil buttered biscuit!

Well none of my puffers are thin, but I think she was puffing herself up a bit when I took those photos, because she's not quite that wide normally. I think she's a bit ruffled because I recently moved her into a different tank.

I know Lisa, they are very cool puffers, definitely one of my favourites. Someone said they were ugly once, but I think they are lovely, I like those kissy lips they have!

[Corvus]

Having two of which one laid eggs (Did you see them personally? Where these really puffer eggs? Where they fertilized?) does not necessarily mean they are a pair. The second one could have been a female accepted by the other one - maybe from the same batch. It's sad both are dead, but it would have been the perfect chance to dissect them and confirm their gender.

So far dissections have not lead to any published measurable gender differences of this species.

Even if your two puffers were a pair, it does not mean that the character you defined (eye difference) is related to the gender. In the target group the eye-snout distance is rather related to different regional variations or species by the way.

Although it is possible that you are right with your assumption, it's equally possible you are wrong. None of the two possibilities can be proofed by the data presented so far. For a proof one would likely need to visit a university collection with a number of these puffers, measure the character in question and determine the gender by dissection. If you find a clear correlation this can be considered proof, so far I fear it's rather speculation, that might or might not turn out to be valid.

[pufferpuggirl]

Darn! I thought I was on to something there. Well, it sounded good anyway. So, a female will just lay eggs, even if a male is not present, and even if they aren't fertilised?

In regards to the "pair" that I had, I thought because they didn't kill each other meant something, but I suppose that can be explained away too.

Bummer!

[LilGreenPuffer]

Darn! I thought I was on to something there. Well, it sounded good anyway. So, a female will just lay eggs, even if a male is not present, and even if they aren't fertilised?

Yep. Eggs don't have to be fertilized to be released; that's how spawning works. The eggs are fertilized outside of the body. Also, a female regularly produces eggs; if there is no male, she will either absorb them back into her body or release them. Usually after releasing eggs like this, she eats them.

In regards to the "pair" that I had, I thought because they didn't kill each other meant something, but I suppose that can be explained away too.

Sure. Fishkeepers don't keep them together because they so rarely DON'T kill each other. (Down the road, you would almost certainly have run into issues as well, if you hadn't lost them prematurely.) If m/f combinations worked out, then roughly 25% of all pairs would be successful, and their keepers would have noticed by now.

[Pufferpunk]

So, a female will just lay eggs, even if a male is not present, and even if they aren't fertilised?

Happens to me every month!

[Flutter]

Hehehe.

[Corvus]

Bummer!

Well it's not proven, but it's not disproven either.
Don't be disappointed, maybe at some point we will look back at this thread and state your hypothesis was right.

I had no intention "to explain anything away", but two fish getting along for a short while does not automatically mean they are a pair.

Even if they were a pair (easy to show by dissection) it does not automatically mean the character you observed is gender related. Imagine an alien seeing a white man and a black woman living together and her having a child. The possible conclusion that white means male would be completely off.

[Flutter]

How well do fish recover from surgery? Do a dissection, sew them back up, and voila! Fish have excellent regenerative abilities, I'd bet they'd heal very well.

[pufferpuggirl]

I know, you're right. It's just that it would be nice if it was something so simple as the length of snout to determine being male or female. I always value your advice and what you have to say, as I like to think I appreciate learning new things -- so I'm not upset or anything, was only joking. Obviously it would be nice if I could be credited with making a great find like that, but I think the chances of that happening are about zilch!
Thanks again Marco.


Makes me wonder though .... in the wild, because the miurus is so radical towards it's own kind, do they only get together long enough to procreate, or do they stay together as a "pair" for any length of time?

[Flutter]

Most fish have no parental care and they're only together for mating which is about as "hands off" as one could get. So, knowing nothing about puffer breeding I assume they're only together to do the sexy and then head their different ways.

[RTR]

Spawning in multiple species of puffer have been observed and some few well-documented. The Aqualog puffer books reports on such, and we did have member repeated spawnings of lurker-predators by a member here in the e early days of this forum. [Are those threads archived PP?]

Generally, the male is the spawn-tender in those observed to date. DPs spawn in plant thickets, which the male prepares and tends. GSPs are reported male-tenders as well, but substrate or rock spawners, and so are the lurker-predators. we know little of the SW puffers spawning, but the Procs seem to be pelagic eggs from the one report that I have, and likely the offspring live in the plankton for some period - as do many marines. All the puffers except the DPs have tiny fry, requiring infusoria to start - that may be due to being secondary FW fish for the FW members of the family, infusoria being as close as we get to plankton.

Breeding requires physiologic readiness, and very likely equally requires the right pheromones. When a female smells/tastes right to the male, it is a compatible pair, until the business is done. Then she become the enemy and leaves the area if male care is standard across the group of FW (&BW?) species at least.

Long term cohabitation is likely an artifact of captivity in our hobby fishes. Harems are observed in several families from both FW and SW in the wild, but the long pairings observed in captivity are a bit unlikely in the wild. We don't know enough about long-term territory holding to even speculate if this can lead to repeated pairings in the wild.

HTH

[Corvus]

Lurkers that have been bred include M. suvattii, M. abei and M. cochinchinensis.

There is a German report from 1973 about breeding T. miurus, but at closer examination the puffers described turned out to be M. suvattii. Nontheless, I think the breeding style of T. miurus may be similar to M. suvattii, at least a lot of their lifestyle is similar.

There is also a younger German report of 3 T. miurus kept together long term (several years in a - I believe - 60-80 gallon tank, it's called an exception), however, I could not see physical differences as stated above. If I remember correct it was written by the forum member Martin Hi. Maybe invite him to this thread. He might be able to add a valuable different view.

No... I would not dissect a living fish kept as a pet just to know its gender. But ones that have died wre a good opportunity.