Swordtail is not a mammal, it's a fish although it gives birth. Another example like Swordtail is Guppy. Guppy gives birth but it's a fish.
A Swordtail is a type of fish that has a sword shape on their tail. Males have them but females don't.
There are guppies and mollies.
Tropical fish flakes
Swordfish, swordtail
yes it is....it is very popular for freshwater aquariums
Yellow Swordtail
A swordtail is a tropical fish and a goldfish is not. The swordtail would need a higher temp. than the goldfish. Depending on where you live it probably wouldn't survive the winter.
When they start having offspring.
no it will not but it would attack if it or it's babies are threatened
At about 6-7 months old
Guppies, mollies, swordtail fish, four-eyed fish, and platies or moonfish. There might be more though.