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FAQs on the Molly Identification

Related Articles: Mollies, & Poeciliids: Guppies, Platies, Swordtails, Mollies by Neale Monks, Livebearing Fishes by Bob Fenner,

Related FAQs: Mollies 1, Mollies 2, Mollies 3, Molly Behavior FAQs, Molly Compatibility FAQs, Molly Selection FAQs, Molly System FAQs, Molly Feeding FAQs, Molly Disease FAQs, Molly Reproduction FAQs, Livebearers, Guppies, Platies, Swordtails

Dalmatian mollies  12/17/10
I was wondering if Dalmatian mollies grow larger than Black mollies??
At the fish store I was at the Black Mollies were listed as growing up to 2 1/2 inches and 4 inches for the Dalmatians. Since it was a big box store I doubted their information, but maybe they were right. Are Dalmatians related to Sailfins which apparently grow to 6 inches? Also are female Black Mollies more peaceful than any other molly?? Thank You!!
<It's difficult to predict precisely how big your Dalmatian Mollies will get. They're hybrids, so there's a fair bit of variation. But you can reasonably expect farmed Mollies to get to about 8 cm/3 inches in the case
of shortfin varieties, and 10 cm/4 inches or perhaps slightly more in the case of Sailfin mollies. The big Giant or Yucatan Sailfin Mollies (Poecilia velifera) are relatively scarce in the hobby, though they may be obtained through good aquarium shops and fish clubs. Do read more about Mollies and their needs here:
Cheers, Neale.>

Re: Tattooed Mollies 09/15/09
I look for an hour to find these fish & understand now why your were surprised. The two white fish I have are balloon molly's
<Balloon Mollies are some sort of mutated hybrid Poecilia species. I'm not wild about them, I have to say, but do read my general comments on Mollies, here:
I was told that they were tattoo for they have purple on one & blue polka dots.
<Now this is something I'm dead against. The tattooing process is known to be harmful to fish, and certainly not done in a way we'd consider humane. Here in the UK, tattooed fish are very rarely seen, with most fish shops having signed up to a pledge run by one of the magazines to stop trading them. But elsewhere in the world, you will sometimes come across tattooed and dyed fish. Please don't buy them.>
Geez I think the Fish Bowl don't know squat about what they are selling. Are they okay with the rest?
<Mollies are of variable value as community fish. In theory they're peaceful herbivores, but they are very sensitive to poor water conditions when kept in freshwater tanks. They are very sickly if kept in soft, acidic
water. On the whole, I recommend people keep them with fish that tolerate slightly brackish conditions, things like Glassfish and Guppies for example.>
Angels on your pillows, Judy
<Cheers, Neale.>
re: Tattooed Mollies
Thanks for the info & will tell people not to buy them.
Not a problem here. But they are really playful & (I know its not true ) but rub against each other & the other fish leave them alone.
<Yes; Mollies are indeed superb aquarium fish in many ways. One of the best in fact. But they do have their "quirks" so it's a good idea to read up on their needs, and act accordingly.>
I did buy a male swordtail he really beautiful but notice the female are getting aggressive. Anyway Neale I do know your busy & will try to leave ya alone & will spread the word about the tattoo thing. I 'm hoping that they use a paint brush to do that & not needles.
<They use needles, hence tattooing.>
will look it up
<The Wikipedia page is accurate and well referenced:
<Cheers, Neale.>

Giant Sailfin molly   5/1/09
Hey Guys,
I placed a link at the bottom of this email and my related question is...Is this the Giant Sailfin Molly that was described in the article about all the live-bearers? They claim the max size is 6.5 inches but the scientific
name doesn't match the one you stated in your article.
<The true Giant Sailfin Molly is Poecilia velifera (Mollienesia velifera, according to some authorities). It is virtually absent from the hobby, and it is 99.9% likely that the fish sold at that pet store is a hybrid Poecilia of some sort. Giant Sailfin Mollies are traded through biological supply houses, and some livebearer clubs may auction them, but in 25 years of fishkeeping, I've seen them in a pet store just once. Partly, it's unpopular because it comes in just one colour -- wild-type green -- and is also extremely delicate, requiring a big, exceptionally well maintained (nitrate-free) aquarium with warm, slightly brackish water. Cheers, Neale.>

Unusual mollies 11/6/08 Hi, folks- I have some unusual mollies in my tank. Mother was a large wild-type, not full velifera, maybe half. Father unknown, as I only have one male, and he is sterile (fancy white Lyretail balloon). The mother dropped two nice broods before passing on. Each brood was made up of about 75% of these unusual fish, with a few blacks and a few wild-types thrown in.  The unusual mollies here have yellowish translucent bodies with black spotting especially on dorsal and tailfin. They have black (rather than silver) pigmentation on the organ cavity lining, giving them a "black-eyed pea" quality. The translucence and black interior combines for a very unusual appearance. The overall appearance is more like a golden wagtail platy than any molly I have ever seen.  In the photo, ignore the fancy balloon mollies and look at the plain-ish young mollies behind them. Sorry for the poor photo.  Might I have a new variety here, and what is the likelihood they will breed true? Ken <Ken, this is clearly some kind of deformed balloon Molly. Since all balloon Mollies are deformed at some level, seeing variations on the theme isn't that uncommon. The genetics will likely be incredibly complicated, and there's no way to test if the deformity will breed true; only careful cross-breeding and observation of successive generations will provide the data you want. I'm not a big fan of Balloon Mollies I'm afraid. To me they all look absolutely hideous! So I guess beauty is in the eye of the beholder... Cheers, Neale.>

More unusual molly pics  11/07/08 A couple of interesting features in these fish, aside from the black organ sac pigment and translucent appearance- they all have very black pigmented eyes, and at half-grown, they show clear lateral segments, as if their flesh was like the segments of an orange, only horizontally. This is much more clear in person than in the photos. <Each to their own I guess! I'm still not a fan of Balloon Mollies, even unusual ones! There are any number of livebearer clubs around the world; you might want to get in touch with the serious Poecilia breeders out there, and see if you've actually come up with something special. Good luck! Neale.>

Wild mollies, ID, sel.   9/27/08
i live in the united kingdom and have kept a few Sailfin mollies. i would like to have a fool grown molly of about 6" and i feel the best way for me would be to raise wild mollies as i feel tank bred mollies may have stunted growth due to cross breeding and interbreeding.
<Your analysis is correct. The Sailfin Mollies sold in shops are primarily Poecilia latipinna, but likely hybridised with other species or else strains developed for colour rather than size. While these Sailfin Mollies can get to about 10 cm or so, they don't ever seem to reach the full 15+ cm lengths possible in the wild for either this species or the related Giant Sailfin Molly (Poecilia velifera). However, genetics is not the only factor. Mollies have been studied by scientists because their size is dependent not just on genes but also the social structure of a population and environmental factors (i.e., diet and water quality/chemistry). In other words, it's complicated. Male body size is smallest in dense populations, in the wild at least, so keeping a single male alongside a group of females might work best. Mollies, like all other fish, grow fastest when young, and while growth slows down as they mature, it doesn't stop. Among breeders, it is said that male Mollies stunt very easily if overcrowded when young, so one approach to take might be to rear a new generation of Mollies at home, and remove some of the males to a very clean, spacious tank so that stunting couldn't occur. This is likely related to the observation mentioned above, that in the wild males are smaller in denser populations.>
can you help me in finding either young wild Sailfin or about 2 pairs of adult wild Sailfin mollies.
<In the UK, wild-type Poecilia velifera or Poecilia latipinna simply aren't traded. If you want them, you have two options. The first is to place a special order with a retailer you can trust. Several stores handle top quality wild-caught fish, for example Wildwoods in London (who do mail order as well as being retailers). What you don't want is a retailer passing on plain Green Sailfin Mollies as wild-caught fish of either species: Green Sailfin Mollies may look the same, but they're captive bred and likely won't get so large. Your alternative is to contact a livebearer special interest group, such as the British Livebearer Association. This group has auctions at which you can buy fish carefully bred to ensure they're not hybrids. These will be cheaper than wild-caught fish, but just as good.>
thank you
<Cheers, Neale.>

WetWebMedia has just sent you $400.00 USD with PayPal, note to place Neale's work    5/23/07 Bob, Thanks for the payment! Glad to be of service. If there's anything else you want from my back catalogue, let me know. <Mmm, likely anything, all that will fit Neale... in time, when you can use the money, relief from incessant, repeat questions that your in-print work will inform, inspire otherwise... Send them on> Curious you still use Mollienesia for mollies. Haven't kept up with the taxonomy, but I agree that there seems (to me, a paleontologist) a need for subgenera at least within Poecilia. The variety within the genus (sensu lato) strikes me as rather wide. <Mmm, a brief stmt. re: I default to "the more/most common" scientific "nomena" for hobby use by and large... With a nod to standard ref. works if this is warranted... "The medium is the message" as one way states this succinctly> It's funny what *doesn't* get printed by magazines. I wrote a piece I thought was rather good on "stuff not to put in your aquarium", basically review of non-aquatic plants, amphibious critters, non-essential additives, etc. Did they want it? No, presumably because "negative" pieces don't play well with the retailers <Too likely so> -- though I think retailers shouldn't sell stuff that won't thrive in freshwater tanks. I guess you have the same argument over coral-eating butterflyfish and fussy nudibranchs. They're in the trade, but why? <Mmm, simple response: "Because they're available and they sell"... Not a real reason/cause per accidens, but is the ultimate rationale. B> Cheers, Neale

Do I have platy or mollies?   9/4/06 Dear Fish Guy(s), Gals? <A male this time>   For the last three months I've had what were sold to me as and I *thought* were platy's. After doing some searching on the web, I found a pic that looks like them (attached to email) and wondering if instead I have mollies? <These are mollies> One of them recently had fry, and a couple are still hiding and alive, my Betta enjoy snacking on the rest. While some people have told me it's "mean" to let this happen, <Mmm, anthropomorphisizing...> it keeps the bio-balance of my tank in order, as I have no place for hundreds of fry to grow up right now, plus Mr. Betta loves the live snacks in addition to the rest of the well varied diet all my fish receive. My question, is if it looks like I've got mollies instead of platys? <Yes> I'm a new hobbyist to the fish world, and watching the fry be born was neat, but I think Wal-Mart inadvertently may have sold me the wrong species, and new me didn't know the difference. <Happens> I enjoyed watching the birth experience and the little specs of rice sized babies swimming around, so I bought a male red-wag platy yesterday - after doing searching online, reading through your site, etc., I am confident that he is indeed a red wag male platy. My new guy is quite horny, moving his "sex fin" (?sp "gonnopium") <Gonopodium> and going after the females and trying to mate but jabbing it in them. Obviously I've read the two species (mollies & platys) are not compatible <Mmm, are compatible usually> but would like more fry. Right now, I don't have a web cam, so been doing searching of online pics trying to figure out what I have so I can either trade or buy either a molly male or trade my current females for what I know are platys at the local fish store. I prefer platys both for the beautiful colors, but I have a small 10 gallon tank and may be a couple months off from upgrading to a larger, starting the new cycle, etc, so right now for fish smaller is better. I have 4 female unknowns, 1 male platy, 1 four year old betta, <Wow, old!> 2 dwarf Corydoras, 1 regular size Corydoras, 1 upside catfish, and 3 (platy or molly) fry who haven't been eaten. Water changes regularly to keep nitrates and nitrites at 0 since I'm sort of overstocked. PH is usually about 7.1 - 7.2, water hardness of 300, alkalinity of approx. 110 (local treated tap water) Thank you for any help on this one. <... Would be looking into another or larger tank... Bob Fenner>

Mollies and Platies and Swords, Oh My! - 04/20/2006 Hello WWM Crew, <Hi, Chad!> I've just spent much time scrolling through your pages on mollies, platies, and guppies.  Found lots of useful info on breeding, feeding, treating, what do to with fry, and sexing... but can't find - maybe I missed it - an answer to my question.  Is there a way to tell a molly from a platy from a female swordtail? <Sure....  though differences may seem subtle until you've seen many of all.> I have a Mickey and a twin-bar, both platies as I believe they're the only ones colored this way.   <Can find some Mickey mouse swords, now, too.> A few days ago I bought an all-white one and an all-red one.  They were labeled mollies at the pet store, but who knows if they even know.  They are all getting along and all look similar, if you ask me, except maybe for the fact that the new ones are slimmer, especially the red one, but it's smaller altogether.  I've seen pictures online of all-red platies, mollies, and swordtails.  Haven't seen an all-white platy yet. <Hmm, where to start, and how not to make it more confusing....  Platies and swords have been heavily hybridized with one another over the years; you will be very hard-pressed to find a platy that hasn't been crossed with a sword or vice verse somewhere down the line.  Some platies even develop small "swords" on their tails.  Mollies aren't hybridized with either of these, and are usually very easy to tell apart.  They'll have sort of....  well, a different body shape....  kinda tough to describe.  I would recommend that you go to a few different fish stores and look long and hard at some of each of these types of fishes; you'll develop an eye for it in no time.> Thanks for your time. <Glad to be of service.> -Chad Soucie <All the best to you,  -Sabrina>

Balloon fishes   2/1/06 Dear Wetwebmedia, <Ivy> What is the difference between a regular Molly or Ram and their "Balloon" version? How did this difference come about? Is one less healthy than the other? Thank you. <The "Balloon" types are "sports", human-made/allowed mutations... same species. "Made" by naturally occurring variation and selection by breeders. Sometimes such mutants are more "aquarium-hardy" than wild-types, sometimes not. Bob Fenner>

Sexing Mollies - 10/28/2005 How do I sex the Balloon Bellied Molly? <Same as with any other molly. If the anal fin is long and "pointed", it's a male, if the anal fin is rounded and "fan-shaped", it's a female.> What colors are they found in? <Mm, I've seen several.> Are there any rare colors? <I doubt it. They seem pretty readily available.> I'm new at this. Just got a new tank set up yesterday for freshwater tropicals. I have 10 Bettas too. I love watching my fish. Please help. <Wishing you well, -Sabrina>

How do I tell if my Molly is a male or female? Hello to all at WWM, <Hello to you!> I have a crazy question. <Can't be as crazy as some of the ones my kids come up with'¦> We bought 2 marbled mollies and were told that one was male and the other female.  Then while paying someone in line behind us said we had 2 females. How do I tell the difference (possibly with visual aid?). I read all through the FAQ's about the differences but I really need a picture they all look the same to me and I can't seem to get a clear image in my head about what the males look like vs. the females. Any help would be most appreciated. <Well, I don't have a picture to send you but if you look closely at their anal fins you can tell by the shape. The anal fin on a female will be shaped much like a fan. On a male it will be thin and pointed. This is the surest way to tell on livebearers.> Thanks in advance for any help offered. Amy <You're welcome! Ronni>

Guppy tail mollies: fertile? Hi Ananda, <Hi again!> Wow!  Where do you live? <Chicago area.> I haven't seen any snow for several years and I miss it!   Consider yourself lucky (if you can stand the extra work it creates!) <The snow here is minimal compared to what I grew up with in northeastern Minnesota!> I'm really writing to answer the question about the two female Mollie's ages.  They were fully matured when I purchased them so I don't really know their true age.  I got them at Pet Smart, so maybe that would give you some idea of their ages.  They look like they came from the same parents because they both have extra long tails (not lyre tails).  Maybe that can tell you something about their genealogy too.  I was attracted to them because of their unusually long tails, almost like male guppies!    <I bet you have the so-called "guppy tail mollies". I've seen those only once, and they were quite expensive. I've been trying to find out more about the genetics of them, but they're so new on the market, it seems no one is talking about that yet. As yours are both balloon-bellied and guppy-tailed, it's possible they're sterile -- I know the balloon-bellied mollies are highly inbred, and I suspect the same is true of the guppy-tailed.> One of the females is also having "the shimmies."  Is that because of the parasites?   <Could be. Usually, thought, when I see my mollies shimmy, I take that as a sign their tank needs some more salt. I have ridiculously hard water, so I can keep the mollies in a freshwater tank, but I've seen that a few individuals are prone to shimmying or pop-eye unless they are in a brackish tank. I imagine you might see that sort of thing more frequently in the highly-bred varieties you have.> What causes the parasites to come from "nowhere" like that.  I mean, I didn't buy new fish with ich on them or at least I didn't notice any. <That last bit is the key -- you didn't notice it, but it was quite possibly there. Ich has multiple stages in its life cycle, one of which is invisible. And here's a question -- did you let any of the water from the fish store into your tanks? If you did, that's definitely something to avoid in the future.> Thanks again, Leslie <You're quite welcome! --Ananda>

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