Livebearers
Hi there, I have had a 20 gallon aquarium up and running for about 4 months.
  I have lost 2 swordtails and 3 mollies, due to stress from a surviving aggressive female molly.  She stressed them out and I figured it triggered fin rot and fungus.  I believe the molly only attacked other mollies, but I can't be certain.
Today I bought 2 swordtails a pregnant female and a male, both red wags.  
The male showed an aggression that I have never seen before and it kinda freaked me out.  He chased the pregnant one a lot, but he also turned around and attempted to stab her with his sword tail.  I have never seen fish mate, is that what this was, or was it outright aggression towards her?
< They were definitely trying to mate>
She seemed very clingy, and kept close to him even though he was attacking her.  
Is this behaviour normal?
< Everything sounds normal>
I've been searching for hours online and I can't find anything that describes their behaviour when mating.  Can you explain to me what they look like when they are mating?
< The male will get up next to her and try and insert his sex organ into the females ventral area. It only happens for a few seconds but it happens all the time.>
He was also nipping at her tail fin as well as her belly fins (I don't know the real name for them)  I have seen my aggressive molly chase male and female mollies nipping at their belly fins, as well as the male molly doing the same.
I have separated the aggressive male from the other females and he has been trying to jump out all night.  He's in a little critter keeper until I can hopefully exchange him at my LFS tomorrow.  Since he's been in the dark for about 4 hours why would he still be trying to jump out?
< The confines of a smaller tank are obviously not to his liking.>
I'm hoping that the move and the aggressive male swordtail didn't stress out my pregnant female too much that she will prematurely deliver her fry.
any answers you can give would be greatly appreciated.
< All of your fish are livebearers. Males tend to be smaller than the females and are always in the mood. Part of the ritual is the male continually chasing the females around and trying to mate with her. You need to make sure your fish are well fed or the females will get too thin and die form being continually chased around. I would do a 30% water change and add a little rock salt to the water to prevent any more fungus and tail rot. I would also add some floating plants like hornwort so your fish have a retreat to get away form the males advances and have a chance to rest. As your fish give birth the plants will also provide an area for the fry to hide until they are big enough not to be eaten by the other fish.-Chuck>
Thanks
Beckie

Crosses between livebearing freshwater fishes
Hi! I have a 10 gallon tank. I own 1 glass fish,1 zebra danio,1guppy,1 swordtail, and 2 balloon-bellied mollies. The swordtail is a male, both mollies are female. I've heard that Platies and mollies have bred. Can mollies and swordtails breed? Thanks in advance, Rebbeca. Cool website!!!! 
<<Dear Rebbeca, I haven't heard of mollies and Platies breeding, but I'm by no means a livebearer expert. Maybe by now they do! Your swordtail will, though. What species is the glass fish? Should probably be kept in a group, and your Danio may tend to aggravate the heck out of your guppy and his tail. Other than that, sounds fine. Just remember to do weekly partial water changes, and test your water for ammonia, nitrite, and nitrates to keep abreast of the toxin levels. -Gwen>>

Molly/Platy interbreeding? (03/09/04)
I've been looking all over the net and cant' seem to find an answer anywhere so I thought I'd ask the experts.
<Just Ananda here today, but I hope I can help...>
Is it possible for a Platy to cross breed with a Silver Molly?
<I have never heard nor read of this happening. They are in two different geniuses, so it would take a lot of work in the lab to artificially cross-breed them.>
Please ease my troubled mind, thanks once again,
Kristen
<Tidbit of info about these fish: livebearers can store sperm for up to six months after fertilization. So even if you have a genetically incompatible pair, you might start seeing fry if you've had the female less than six months. And the male will probably try to mate with the female. Have fun with your fish! --Ananda>

"Big lip" on mollies (12/24/03)
<Hi! Ananda here tonight...>
I just started up an aquarium and two of the mollies that I started with have gotten a "big" upper lip that stops them from eating.  One has died and I am trying to save the other.  The upper lip looks really thick and turned up.  
Thanks for any help.
<This is not something I've seen before, but there are a couple of things I suspect. One, if the tank was not cycled before the mollies were added, the ammonia and nitrite from the cycle probably hastened the fish's demise. The other possibility is some sort of infection or parasite  that the mollies had before you got them. You might try Kanacyn or Spectrogram, but without more information about this, it's difficult to diagnose. --Ananda>

Guppy With A Dark Side
Hi everyone =)
<Hi there! Scott F. here today!>
I've just started a tank with around 120L of water (um...I'm sorry I'm from Australia...) for tropical fish. Basically a week ago I got one guppy, one molly and one swordtail. In the beginning, the guppy constantly kept stalking/chasing the swordtail.
<Wow- I would have expected it the other way around!>
When she (the swordtail) died two days later, I guess I attribute it to it being a new tank.
<Well, stress from being chased around by your crazy guppy could have been a cause, too>
The guppy stayed by itself for one day, but then took up to chasing the molly (very scary sight actually...). Now the molly is sitting at the bottom of the tank. [ok let's describe the molly: its moving fins and tail (therefore not clamped fins)
really fast, but it cant seem to get up. Is this a disease? I cant find it in your FAQ... and it was perfectly fine yesterday. it also seems to be gulping..]. Are these deaths likely to be related to the scary guppy??? PH is 7.0, temperature is 26Celcius, and my local store did a test in which they said everything was fine as well. Thank you so much in advance... Scared owner: ally
<Well, Ally, I'm thinking that the deaths are definitely attributable to the guppy chasing these victims all over the place. In the absence of other obvious problems (flawed environmental conditions, blatant disease symptoms, etc.)- this is my call. In my opinion, you could rectify this aggression by one of two techniques: Either remove the guppy to a separate tank, or add several new fishes at one time, including several female guppies, in the hopes of distracting this guy's attention from one poor fish...Hope this helps! Regards, Scott F>

Goldfish and Plecos and platies, oh my!
Hi,
<Hello, Sabrina with ya today>
Firstly let me thank you for running a brill website and giving guidance to so many people.
<Thanks>
I'd now like to ask for your advice about three things: I have been running an 8 gallon aquarium for over a month containing a pair of sunset platys, a Pleco and two veil tailed goldfish (The goldfish co-exist very peacefully with the platys and all fish seem happy).
<Woah.... Wait a minute....  Eight gallon tank?  Yikes.  FAR too small for goldfish or Plecostomus, I'm sorry to say - goldfish should be kept with something like 15 US gallons per goldfish, as they are extremely messy fish, and can potentially get rather large.  I have several in my pond that are about eight inches long.  And Plecos - well, there are certainly some plecs that stay small, but the 'generic' plec gets nearly two feet in length....>
Last week, while I was away, the female platy (Daphne) bit off the fins of the male (Derek) and he could no longer swim and he died. Is it normal for females to attack males? Daphne was always the calm and tranquil one and Derek was the aggressive crazy one, chasing her around. Have you ever heard of this happening before? Some guidance please!!  
<I have, on occasion, seen female livebearers get quite ticked off at being harassed too much by a male, and become a little aggressive.  To remedy this, keep two to three females per male.>
Also, at feeding time that is once every two days, one veil-tailed goldfish sort of swims into the other one's tail, so it is in between the two long tails and is right behind it. We do not know yet their genders since the are too young for us to tell. This is only at feeding time; the rest of the day they are good mates. Is this normal?!  
<Could very well be - maybe a bit of flirting, or just playfulness - also have seen some goldfish chase others for their poo....  gross....>
Thirdly, now that we no longer have a pair of livebearers and we wish to raise some fish from babyhood and your website is against goldfish and tropicals in the same tank, are there any coldwater fish that give birth to live young, that are suitable for a beginner to raise in a tank and are compatible with the fish I already have?
<Well, first off, goldfish in an 8 gallon tank is not a good idea.  The water will become foul quite quickly/easily.  Trying to raise baby fish in such conditions will result in many dead baby fish, unless you're doing water changes extremely often.  My biggest recommendation to you is to either find the goldfish a new home or get them a bigger tank (or pond), preferably in the neighborhood of 30 US gallons or more, and stick with livebearers in the 8g.  Maybe two males and 4-5 females, if you choose to stick with platies.  Perhaps upgrade tank size when the Plecostomus gets too big, or find a new home for him when he outgrows the current tank.  8 gallons, US or UK, is just fine to raise livebearers in.  Do be aware, though, that they will eat their young, so a lot of hiding spaces or floating plants will help out a lot>
If not, which egg-laying coldwater are suitable? Will the eggs be eaten? (We have a breeding trap).
<Egglayers are a little tougher to breed, but I understand white cloud mountain minnows are pretty prolific (never tried to breed 'em, myself) and can tolerate coldwater conditions - however, the goldfish will get easily large enough to eat white clouds.  I understand zebra Danios can take coldwater, as well.  Also the breeding trap type devices are of little use with most egg layers.  The best bet is to have a lot of cover in the tank - again, floating plants are a big plus, also plants like java moss.>
Best wishes and thank you, London
<And best wishes to you, too.>

Help! I think my platy is dying!
Hey Crew--<Hi>
I have had Lucifer, my male Sunset Fire Platy for 8 months, and he has always been the dominant fish in the tank. Over the past eight months, he has seen about 4 or 5 of his comrades die and not soon afterwards, they were replaced with new friends for him. I have always had either 2 or 3 platies in
the tank, and they're the only breed. I currently have Lucifer and Sushi, my female Sunset Fire Platy.<ok. if he keeps on killing his "friends" then don't purchase more! he obviously doesn't want any friends and is anti-social lol>
Recently though, Lucifer<very fitting name lol> does nothing but hang out in a bottom corner of the tank and he just rests on the gravel. Sushi, who always used to get chased by Lucifer, now swims alone towards the top and occasionally comes down to the bottom to nudge Lucifer and come get him to play, and sometimes her nudges get him to swim around, but never for more than a few seconds. After that, he just goes back to the bottom. He kinda leans to one side and looks like he's hatin' life, but there aren't any other noticeable physical differences. He's always gotten excited about eating his blood worms, and that hasn't changed either. He'll eat, but then retreat back to his corner in the bottom of the tank. I've read all of the common ailments of platies, but he doesn't really match any of them. Could you please tell me what's wrong with him and whether or not there's anything I can do?<I wouldn't do anything right now. as long as he is eating he should be o.k. fish that eats is a fish that lives". or at least that is what I believe and what ScottF believes> He's one of the original 2 that I started out with, and I've become really attached because of I've had him so long and because he's so dominant. He's not acting like himself! Please help me and Lucifer!<just test the water and keep a close eye on him. no point in stressing him out over nothing right now. Good Luck, IanB>
Thank you,  Alison

Platy Breeding
<Hello.>
I have a platy question.  Is it a big deal if platies inbreed and if it is a big deal could it have health risks?  I haven't had to face that problem yet with my platies but I was just wondering for the future.  
<Well, any inbreeding is a concern to some extent, but livebearers especially are extremely inbred for color, fin shape, etc.  The most important thing is that you avoid breeding fish with obvious undesirable genetic deformities, and be sure to cull the brood - 'weed out' any misshapen/deformed young.  These culls can be used as food for larger fish.  -Sabrina>

Freshwater Fish Missing - 8/20/03
Hello, 
<Sorry for the delay> 
My name is Tara and I have had a 10 gallon freshwater tank for 3 weeks now, with 3 neon's, 2 sliver mollies, 1 male guppy, 1 gold dusted molly, and I had 2 sunset fire platy's but one disappeared. <Tara, you have a quite a few fish for a newly set up tank. I suspect there might be some problems with water quality.> 
I believe the other fish ate her. 
<Only after the fish died would these type of fish likely consume another fish and even then it is very unlikely. It might be best to do a thorough check of the tank which may include moving stuff around.> For what reason I do not know but I searched for the fish inside and outside the tank and she is still missing. 
<Maybe the filter?> 
My other sunset fire platy fish I believe is pregnant but I'm not sure because I don't know much about fish. 
<Could be a sign of disease.> 
When I first got her she was small and thin. Now on my 3 week of having this fish tank my fish has become longer and her belly is very round and low. Could she be pregnant or is she just one fat fish? <Maybe pregnant as this is not unheard of but could also be a sign of problems.> 
Plus my male guppy has been by her side all the time and he's been nipping at her back-end. 
<Well, possibly pregnant> 
I feed all my fish 2 times a day. (I read in a fresh water tank book that you should feed about 2 times a day is that too much?) 
<No, just enough for all fish to eat with little to no waste, two times a day is fine> 
All my fish seem to be very happy. 
<Very well> 
I went out today and bought a breeder trap and put the pregnant fish in it. 
<Should be fine>
Although she doesn't seem too happy and neither is my guppy. I believe she has 2 weeks to go. 
<Not sure myself> 
Should I leave her there until she has the babies or take her out and put her back in the trap in few days before she has the babies? 
<No need to move her again as this might stress her out and she might lose the clutch. Leave her be. Please read through the freshwater section on our site. So much knowledge to be gained. Keep us posted. -Paul> 
It would be a really big help in hand of what to do with my fish that would be great.  Sincerely,  Tara

Swordtails
>I have a male swordtail and 2 female swordtails (I think) and I'm trying to breed them. The swordtails are different than the ones I've been seeing on the internet. They are orange with black splotches all over them.  
>>Hello Loyd, Marina here.  Most likely simply a variant, there are MANY.
>One of them has a small tail and the others have bigger tails but no sword. I don't know which one is male and which is female.
>>Quite right, and easy enough with a good set of eyes and a bit of patience.  The real trick to sexing livebearers is the paired anal fins: in males they are noticeably pointed, and rather thin, whereas in females they are quite rounded, fan-shaped almost.  Also, males will tend to have slimmer bodies, whereas females appear to have a fatter abdomen and a somewhat wasp-waisted shape.
>If one does get pregnant how will I be able to tell? If I put the pregnant female in a breeding tank could I use peat moss as cover for the babies? Thanks a lot.
>>Yes, you can use peat moss, although there is also plastic grass available that can be cleaned and sterilized far better.  Marina

Red Wag Platy - and a Whole Slew of Other Stuff
Please Help a newbie to the hobby,
<Sabrina here, to try to do exactly that>
I am VERY new to the fish experience and am learning quickly.  Three weeks ago,  I gave each of my six year old twins a 1 1/2 gallon fish tank for their birthdays.  We followed the pet stores set-up instructions.  Came back a week later had the pH tested and then bought our first fish.  We purchased two red wag platies.  They were small, so we put them in the same tank.  One died within the week.  So we took a water sample to the store and got a swordfish for replacement.  In the other tank we got a red tail shark and a male guppy.  The red tail shark died within two days.  We took a water sample in ( they didn't test it) and got a female guppy.  NOBODY in all of this tested my water or said hey you should test your pH.
<Okay....  It's definitely time for a new fish store!  Where to start....  Well, first off, please understand that 1 1/2 gallons is a really, really small space.  Not many fish can squeeze into there comfortably - the only fish I'd recommend for a 1 1/2 gallon tank is a single male (or female, if you like 'em) Betta splendens (Siamese fighting fish) - please never put two males in a tank together, though, as they will fight to the death.  They don't require filtration or aeration, nor do they need a heater, and they're very tough, beautiful fish.  Next, the red-tailed shark reaches nearly five inches in length, and gets to be an aggressive fish - won't even fit in a 1 1/2 gallon tank, shame on your fish store!  Also, double shame on them for not testing your water!  Definitely get a test kit for pH, ammonia, nitrite, and nitrate, if you don't have them already.  These are the things your fish store should have sold you, not more fish!  Also, are you using a tap water conditioner, to remove chlorine/chloramine?  This is also quite crucial, as chlorine/chloramine is toxic to fish.>
The male guppy aggressively chased my female guppy, so I had to separate them within a few hours.  So, we put the original red wag platy (now about two weeks with us) in with the male guppy (now about 1 week with us).  This combination worked well.  HENCE, my first discovery that male guppies can be very territorial.
<Well, it's not so much a territory thing as that the male was trying desperately to breed, and the female probably wasn't very interested.  Best to keep these fish in something larger (even a 10 gallon tank would suffice) where you can keep 2-3 females per male.>
The sword fish ( about a week with us) and the female guppy ( one day with us) were paired together in the other tank.  This seemed to work well.  We had harmony for two more days.  Then our female guppy dropped about 15 babies.  She proceeded to die the next day.
<I'm sorry you lost her!>
So, now we chose to move the swordfish into the male guppy's tank while we set up a third 1 1/2 gallon tank so that he would not eat the babies.  The male guppy tormented the sword fish so bad that we had to put the swordfish into the third tank before the guppy killed / stressed it to death.  HENCE, our second lesson swordfish that have swords are males and won't get along with testosterone driven guppies that are 1/2 their size!
<Well, check and see if your swordtail is a female, too; the easiest way to tell is to look at the anal fin (that's the fin on the belly of the fish, near it's tail).  If this is round and fan-like, it's a female.  If it's pointed and thin, it's a male.  Look at your male guppy for reference on what it should look like.  I've seen male guppies try to breed with female platies, and swordtails aren't that far off.>
Now the swordfish started swimming funny.  He died 24 hours later.  I didn't think and didn't know to test its pH.  WOW, was it off.  Hence,  third lesson always keep an eye on pH.
<Well, unless the pH is changing drastically, or is way out of the fish's tolerance range (most livebearers can take anything from 6.5 on up to 8.0), it shouldn't be the root of the problem.  I'm thinking this (and the other deaths) is more likely related to ammonia or nitrite, as those are very toxic to fish.  Please check out the 'cycling' FAQ's at http://www.wetwebmedia.com/FWSubWebIndex/estcycfaqs.htm - this will give you a bit of an idea of what's going on in your tanks.>
Within two days the male guppy and the red wag platy developed ICH.  Hence, fourth lesson - It is great to live near a 24 hour super Wal-Mart so that you can get ich treatment at midnight.
<Oh, yikes!  Anything that can go wrong....>
We lost the male guppy before I figured out the ammonia is a second important component to healthy fish.  Now we have got the water "de-ammonia-ized" and my red wag looks great.  
<Indeed, ammonia is extremely important - the best way to be rid of it is simply with water changes.>
We have experienced all of this in less than 3 weeks.  My red wag is still in isolation because it has been only a week since the first signs of ich and she has only been totally ich free for about two days.  Plus, I don't want her to eat my 3 week old baby guppies.
<Here's an article on freshwater ich, so you can better understand the lifecycle of this nasty parasite: http://www.wetwebmedia.com/FWSubWebIndex/fwich.htm .  Hopefully it's been wiped out by the medication - NOT a fun parasite to deal with (not that ANY are....)>
Now lesson #5,  Female guppies have a tiny black spot on their bellies and they should be sexed and separated from their male counterparts by week 4 if you don't want more babies! !  Wow, I can't believe I am still hanging in there.
<Yup.... this little livebearer is sometimes known as the "Millions Fish" due to its extremely prolific nature.>
I now have perfect pH and non-existing ammonia in all my tanks.
<Good.  What about nitrite and nitrate?>
MY QUESTIONS ARE -
1.)  How do I tell a male from a female in the red wag platies?
<Same way as swordtails, guppies, and most other livebearer - look for that pointed anal fin of the male, rounded fan-like anal fin of the female.>
2.)  Will I have the testosterone driven issues with a male red wag plates that I had with my male guppy?
<Well, possibly, but again, this is a drive to breed, not aggression.>
3.)  My water has a tendency to get cloudy in my small  1 1/2 gallon tanks.  The tanks don't have any filtration.  They use only a air stone.  Am I doing something wrong or do I just need to get one of those very small filtering systems for small tanks?  In the one tank, I only have the red wag ( that been receiving medication for ich over the past week).  The other tank had the 15 baby guppies.  I moved the 5 females out of there today.  I think there is another one or two females I can move out, but they need another week for me to make sure they are females.
<Well, part of the cloudiness is probably attributable to the tanks cycling.  I would very, very strongly recommend getting a ten gallon aquarium for all your fish (perhaps minus the babies).  This can be gotten quite inexpensively as a kit at a Wal Mart or most any pet store, but please be sure to get one with fluorescent lighting, NOT incandescent lighting, as the incandescents get too hot and can really mess with your tank's temperature.  It may cost a touch more, but it's worth it.  Most kits come with a hang-on power filter, which is far and above what I recommend to new aquarists.  The kit should also come with a tap water conditioner for removing chlorine/chloramine from your tap water.  The reason I am recommending this is that, as I mentioned earlier, 1 1/2 gallons is really a TINY space to try to keep fish in, and it will be nearly impossible to keep ammonia and nitrite at zero; it's also impossible to filter these tiny tanks efficiently.>
4.)  How important is it that I check for Nitrates?
<Well, nitrates are only toxic to fish in very high amounts, and livebearers are tough little fish - but in such tiny, tiny spaces, water quality can quickly get out of hand, and the nitrates can easily get to toxic levels.  It's definitely a good idea to have a test kit on hand and check occasionally.  Far more important, though, it nitrite, which is nearly as toxic as ammonia is to the fish, and definitely needs to be checked, as it is the second step in the nitrogen cycle (again, I recommend you to the Cycling FAQ's).  Ammonia and nitrite, anything above zero should be considered toxic, and should be remedied with a water change.>
5.)  I read from your site that guppies and plates like a little salt in their water.  How do I know how much to put in?  What should my pH be if I add salt?
<In my tanks, I use one tablespoon of aquarium salt to every ten gallons of water.  Some people prefer to use one tablespoon to every five gallons.  In a 1 1/2 gallon tank, probably one-third to one-half of a teaspoon would be about right.  But do keep in mind that salt does NOT evaporate, and after adding it initially, do not add any more when adding water due to evaporation, ONLY when you do a water change.  Again, tanks this small are going to be so difficult to dose, I really, REALLY recommend upgrading to a 10 gallon tank.  Or even larger, if you like.  As far as the pH goes, again, livebearers are tough little fish, and can tolerate a very wide range of pH - the important issue is to not let the pH fluctuate - a steady pH that's a little low or a little high is far better than a ph that is constantly fluctuating.>
Thanks for all the help.  I have two local pet stores and they do not seem very knowledgeable in the fish area!  Lisa Stubbings
<Unfortunately, it seems a lot of pet stores don't seem so knowledgeable, at times.  Try to find a small, privately owned store dedicated to aquarium fish only - they often have much more knowledgeable staff and might be better able to help.  But even with their advice, I also urge you to do research on any fish you are interested in before purchasing, to prevent ending up with things like a five-inch mean red-tailed shark.  I wish you much better luck, and keep us updated!>