How Much Does Swordtail Fish Ownership Really Cost?

Swordtails cost about the same per fish as a molly, but they're the common livebearer that outgrows a 20-gallon starting point the fastest.

The Fish: $3 to $25, More for Lyretail and Specialty Patterns

Standard assorted color swordtails run about $3 to $6 each. A six-pack of assorted swordtails sells for about $29.99, roughly $5 per fish, in line with typical retail pricing. Hi-fin and lyretail varieties cost more: a hi-fin lyretail six-pack runs about $37.99, about $6.30 per fish. Rarer patterns, koi, neon, and red velvet swordtails among them, can reach $15 to $25 or more from specialty sellers.

Upfront Setup: $170 to $345, More If You Size Up

20 gallons is the genuine floor for a small trio, one male and two or three females. Retail listings give a 20-gallon minimum for standard swordtails, but recommend at least 30 gallons, well planted with plenty of room to swim, for hi-fin lyretails of the identical species, and that more generous number shows up repeatedly once you look past the bare minimum. Swordtails are simply more active, open-water swimmers than a molly or platy of similar size, so the comfortable starting point costs somewhat more than the table above, since a 29 or 30-gallon tank itself runs higher than the 20-gallon product linked here.

Live plants aren't just decor here either. A male swordtail can be a persistent, near-constant presence around a female he's courting, and dense planting gives her somewhere to break line of sight, a genuine practical reason to budget for real cover from the start rather than treat it as optional.

Ongoing Costs: $20 to $35 a Month

Food, water conditioner, occasional filter media replacement, and electricity for the heater and filter make up the bulk of the monthly cost. Taken together, full monthly upkeep on a properly sized setup commonly lands around $20 to $35, a little higher than a molly's, mainly because a bigger, more active fish in a bigger tank eats a bit more and runs a stronger filter. Swordtails are also true dietary generalists rather than the more herbivore-leaning molly.

Vet Costs

As with most aquarium fish, swordtails rarely see a vet in any formal sense. Most swordtail health issues, ich, fin rot, and dropsy among them, get managed at home with water quality correction and over-the-counter medication rather than a clinic visit. Dedicated aquatic vets exist but are uncommon and rarely necessary for a species this hardy.

Lifespan

3 to 5 years on average with stable water quality, the same range as a molly or platy despite the size difference. A molly is the closest comparison, a similarly priced fish that gets by on a smaller tank.

The Cost to Plan For: More Fish, and Possibly the Wrong Fish

Swordtails are livebearers, and a mixed-sex tank produces fry on a monthly rhythm. The cost is not the fish: it is the second tank, the extra food and the time spent finding homes for juveniles, or the decision to keep a single-sex group from the start.

The more species-specific risk is hybridization. Swordtails and platies both belong to the genus Xiphophorus and interbreed readily, deliberate crossbreeding between the two has gone on for close to a century, and by most current accounts most swordtails already sold in the hobby carry at least some platy ancestry from that long history. Keep an unplanned mix of swordtails and platies in the same tank, and the fry you end up with may not be cleanly one species or the other, worth knowing before combining the two just because they're both easy, inexpensive community fish.

The swordtail also shows up alongside the platy and molly in our roundup of Three Livebearers That Breed Whether You Plan to or Not. The Swordtail encyclopedia profile covers the fish itself.

Sources & Further Reading