Aquarium Fish


The Swordtail comes in many different colors with the males being easily identified by their signature sword like tail. This is an extremely hardy fish that can adapt to a wide range of water conditions.

They are livebearers which means that the baby fish come out free swimming. Like their livebearer counterpart, the guppy, this is a prolific breeder and a female will give birth about once every 28 days. If you are interested in breeding them, please check out the breeding livebearers page for more information.

Some hobbyists have reported problems with aggression among males when keeping multiples. It may be a good idea to limit the number of males in your tank. A good mix may be three females to one male.

They will eat most fish foods including flakes, frozen, freeze dried and live foods such as brine shrimp.


Swordtail Fish Xiphophorus helleri
Neon Type


Fish Care Detail

Scientific Name : Xiphophorus helleri

Common Names : Black, Gold Tux, Green, Lyretail, Neon, Red Simpson, Spotted, Red Velvet, Black Velvet, Belize, Atoyac

Care Level : Easy, good fish for freshwater fish beginners

Size : Up to 5 inches (13 cm)

pH : 7 - 8

Temperature : 72°F - 82°F (22°C - 28°C)

Water Hardness : 9° to 15° dH

Lifespan : 3 - 5 years

Origin / Habitat : Central America

Temperament / Behavior : This is a tough litte fish. They can take care of themselves when there are bigger fish in the tank. The males may become aggressive towards other males.

Breeding : They are livebearers, so it is fairly easy for them to breed. Be sure to give a lot of floating cover for the baby swords. Try to put the babies in a separate tank otherwise the adult fish will eat them. Check out this breeding livebearers article for more information.
If you want to try and raise the babies look into investing in a breeding box or breeder net like the following:

Aquarium Size : 10 gallon or larger

Tank Mates : Don't keep with tropical fish big enough to eat them. They should be able to handle themselves with many fish their same size or larger.

Fish Disease : Freshwater Fish Disease - Diagnose, Symptoms and Treatment

Diet / Foods : Omnivore but they need some greens in their diet. They will take flake, freeze dried and live foods.

Tank Region : All over the tank

Gender : Easy to determine - the male has a signature long anal fin.

Site References :

Fish Forum : Swordtail Forum

Forum Avatar :
Red Velvet


From: Tammy via email
Hi. I have a female that had babies last night. When I realized she was having them I moved her and the babies to the breeding net. When I woke this morning the babies were dead (except 2). I moved the mom out and left the 2 babies in the net. Can you please tell me what might have caused the babies to die???
Hi Tammy. Without more information (such as ammonia, nitrite and nitrate levels) I would only be guessing as to what caused the death of your baby swords. Here are some possible causes:
  • If it is a new tank that has not completed the aquarium cycle yet, you may have high ammonia or nitrite levels which are very toxic to fish. These are hardy fish that can sometimes tolerate these high levels but I don't think the babies would.
  • If you have a cycled tank but haven't changed the water recently, your nitrate levels may be very high. Nitrate at low levels is not very toxic to fish, but at high enough levels it can become toxic to them. The babies may not have been able to tolerate the high nitrate levels.
  • Sometimes your water parameters may be fine, not all babies make it. This could be attributed to the heavy inbreeding of the many types of tropical fish. Breeders go for certain colors and in so doing inbreed multiple times, thereby weakening the genetics of these fish. It's sad but true.
Since these are livebearers, you will most likely have another batch of babies in about a month. Check your water parameters and let us know what you find out.

From: CC
I bought three swords and they all died within a week. All of the conditions were right so I don't know what happened. They looked and acted normal except for right before they died they just swam in one spot and didn't move or eat. None of my other fish have died, just the 3 swords. Anyway, I am not going to get them (or buy fish from where I got them) again.
Sorry about your fish. This fish is usually fairly hardy and one of the last ones to die if the water parameters are out of whack.

From: Emily
How would you properly care for the baby fish?
You can give them finely crushed flake food, baby brine shrimp and/or finely crushed freeze dried blood worms. To get the best growth rate possible, try to change the tank water frequently, about once a week. You also need to siphon up any uneaten food so that it doesn't foul the water. Thats when keeping them in a tank without gravel really comes in handy.

From: Chris Saunders
How do I get my female pregnant? I have one male and two females in the tank right now but I don't know what will help them breed.
Provide them with good water by performing frequent water changes and then wait. You could try bumping up the water a degree or two for a few days and see what happens.

From: Debbie
How do I know when my female swordfish is pregant?
Look for a growing belly and a dark spot near the anal fin. This dark spot is also called the gravid spot and it may be difficult to see in some species of swords like the red velvet.

From: Emlee
I have been breeding them and they are so amazing! Just watch out if the lid is off the tank, your swords WILL jump out!

More Tips

Related Fish Profile Articles

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The Endler's livebearer species might be extinct in the wild. They have very similar care requirements as the guppy and the two are closely related.
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One of the first species for beginning hobbyist to breed. The Guppy is a prolific breeder that can be quite hardy and colorful as well. Keep males separated from females if you don't want baby guppies!
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