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sexing calvus- tips?


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Can anyone give me some tips on sexing calvus??

I have had 6 calvus for about 6 weeks now, Four of them are around 6-7cm, whilst the other two are smaller (4-5cm). Are the bigger ones mature enough to sex?. I am fairly certain that one is a male, as he has longer perctoral(?) fins compared to the others, has a 'bump' on the head, and defends his shell the most.The others however, which arent that much smaller than the 'male', arent as easy to get an idea. They dont seem to fussed about each other or the male. They all seem to stay near (or in) their respectvie shells/caves with little interaction. If anything, the smallest of the lot gets chased away when he goes near any of them.

The plan is to keep 1 male with 3 females, when they work each other out, and move the remaining two to another tank or trade them. I will post some pics when I can get it to work.

They are in with two Peacock 'Otter Points' juveniles, and 2 small plecos which works ok.


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thanks frenchy,

darker calvus

lighter calvus

Of the four larger ones, one is quite dark, well banded, darkish brown, the others are more of a yellow-brown, and the stripes are quite diffuse around the head. Pics are attached.

All have the white spots on the body, are they all the same type?? I know they grow like snails move, but at what size should they become easier to sex?

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Ok I'll give it a try.

Generally size, shape and pointed fins are helpful indications. But if your fish are young, then it can be misleading.

I usually look at the breeding tube. Having identified a male already will help a lot. You can then compare the breeding tubes.

Here's a drawing of what to look for.

user posted image

The male's tube remains the same thickness the whole length of the tube, whereas the female's tube starts out thicker at the base and comes to a point.

It also depends on the age of the fish. Older specimens have thicker tubes, younger fish have much thinner tubes. I have found that young males have tubes like a fine thread.

It may take you hours to figure it out, then the next day you may change your mind laugh.gif

btw, at 6~7cm you should be able to sex them.

HTH. fins

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The place in question has crossbred calvus's ie CalvusXcomp. This is what is plaguing the hobby these days and it is not easy to differentiate when they are small. This is why I am relecutant to buy calvus's through my own experiences of not getting the real thing even though they are such lovely things.

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Your not going to hear it from the horses mouth if thats what you mean... Put it this way.. I live in WA and im getting fish from sydney just to make sure that this exact problem isnt involved with mine.

All you have to do is see them to know something is up, and most of us here in perth have.

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Fact 1 - the fish for sale as Altos in this and a lot of shops in WA are very dubious to say the least.

Rumour 1 - was stated that the fish were crossed gold comps and black calvus.

Fact 2 - the parents of most of these fry have been sold to a wholesaler along with a horde of fry.

Fact 3 - the retailer will tell customers that a black calvus can be either black, white or yellow or any range of shades in between.

Suspicion 1 - these fry will probably be distributed Australia wide before long

Suspicion 2 - not enough homework is being done by people before investing in fish like these

Suspicion 3 - the Alto market will not be very nice in a few years time unless a concerted effort is made NOW to erradicate/not buy/not breed/not support sellers of these fish etc etc etc and the list goes on.

Hope this clarifies it a bit for you and many others who are not aware of the situation as it is. wink.gif

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Hi fins,

As Anita has pointed out, it is true. I know where the original fish came from and personally saw A. compressiceps and A. calvus breeding in the same tank ohmy.gif Now they are widespread over Australia due to indiscrimate shipping. It is not just one shop selling these dubious fish....there are a number of lfs in WA (and I presume elsewhere in Australia) with these fish in store.


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Also if your wondering why these fish have been singled out its because of the yellow underbelly. These fish should not have any yellow in them. They also have a shorter face than your normal blacks. I was caught out with a pair of these fish a couple of years ago. After the bird flew off them rolleyes.gif they turned into a white (badly washed out) and a lemon yellow calvus mad.gifcry2.gif Trying to find nice calvus in Perth is hard and I agree with Anita on the concern of these fish being wholesaled around the country. I'd consider a nice colony of blacks to be a pretty good investment in the future!! thumbsupsmileyanim.gif

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