Common Name- Rio Otapa helleri Sword
Water Conditions- Temp
70-78, Some water movement,
Behavior- A peaceful, large community
fish. As with all swords, dominant males can be territorial.
Breeding- May eat fry.
Females can be separated to drop fry.
10-50 Young after approx.30 days.
Size- 5-6 inches
Like all swordtails, these require good water quality of
aerated, moving water where water changes of at
least 20% a week are done. Frequent feedings of high quality
food ensures that they will grow to their
maximum size. When first obtained in 2011, it was noticed
that, at least in the water here, of a group of
10 fish, 2-3 would be females, the rest males. Smaller
maturing males are not uncommon, but most will reach
reach a large, impressive size of at least 4 inches
(including sword), and many will come close to or surpass
After many months of
trying a variety of means to address the sex ratio problem, a
portion of the male
overabundance appears to have been turned around by focusing
greater care and feeding of the new young-
primarily by providing more finely ground high quality food
in multiple daily feedings in addition to
the newly hatched baby brine shrimp they had been receiving.
It appears the fry are better able to consume
the smaller particles than the larger flake or pelletized
foods. A .3mm pellet food used here for most fry
was possibly too large for the Otapa fry, and after grinding
that food down even further, the sex ratio
issue seems to be improving.
A recent visit across country confirmed that others keeping
this fish are also experiencing an overabundance
of males, and it may be possible that the sex ratios will even out as
they are kept for longer term in the hobby.
Pre-sexed adolescents are distinctive in that they all show a
dark brown, body length horizontal stripe,
unlike other types of swordtails. They are at their most
attractive as they leave that stage, where most
males develop a yellow/gold stripe above the brown strip as
they sexually mature and develop a sword.
As they continue to mature, the dorsal will develop strong
red markings, and the markings on their sides
will diminish somewhat. Black spotted markings occur
The adult breeders are kept here in a 55 gallon tank with
lots of fine leaved plants, primarily Bolbitis
fern, and young hide within the plants to be removed and
raised separately. When well fed, not overcrowded,
and with generous, effective places for fry to hide, the
adults have not been enthusiastic about eating fry.
But being a bigger fish, I remove fry whenever they are seen.
At a recent show in California, a breeder had begun to
isolate males possessing the brightest yellow stripe.
He has said he is going to breed to develop only males that
possess it. Whether selectively breeding for that
will increase how long the developing males hold on to it is
unknown. A spectacularly large, pond raised trio
with a male displaying a bright reflective yellow stripe was
being sold for $100! At this point he has only
begun with a pair to work with, and whether this line will
breed for that needs to be seen.
To my knowledge, this fish, as new as it is to the hobby, has
not been crossed or hybridized, and those
keeping it are still working on the best means to keep and
breed this large, distinctive helleri swordtail
See other Care Guides