Apistogramma sp. “Xingu”

Apistogramma sp. “Xingu” (A37) is a seldom-seen species from the Rio Xingu in eastern Brazil. They are very rare in the hobby which is unfortunate as they are an attractive species and generally make good aquarium fish.

Apistogramma sp. “Xingu” general information

Apistogramma sp. “Xingu” are attractive and fairly easy to maintain. Like many Apistos, several varieties or color forms are found in the wild. Unfortunately, all forms are rare in the hobby. The only variety of A. sp. “Xingu” I’ve kept was introduced as A. sp. “Rio Xingu Red Lobes” which I got at the 1997 American Cichlid Association conference in Chicago. They were brought to the conference directly from Brazil. This color form was distributed in the hobby at the time but seems to have been lost in captivity and I’ve not seen them offered for sale for many years.

Males of the A. sp. “Xingu” variety I kept were generally a silver base color with a yellow head area. In some, the anal fin exhibited a blue color and many males had red markings on the upper, lower, or both lobes of their tails. The red color is highly variable and I’m sure that with a concerted breeding effort males with very red tails could be produced. However, I never selected for brightly colored males as I wanted to maintain the strain as close to wild appearance as possible.

A. sp “Xingu” classification and species confusion

A. sp. “Xingu” is placed in the Xingu complex of the Regani group and shows features from both the A. regani and A. caetei complexes. Like many Apistos, Apistogramma sp. “Xingu” has been collected in multiple variations and there is confusion about which of the known forms are A. sp. “Xingu” and which are yet-undescribed species.

The area of Brazil they come from seems to be poorly sampled and there are very few accounts from hobbyist collectors. In addition, the construction of the Belo Monte Dam (completed in 2016) created a vast reservoir that flooded many collection locations. Given all this, it will take a lot of effort in the field and in the lab to determine the classification status of these species.

Apistogramma sp. “Xingu” in the wild

A. sp. “Xingu” originates from the middle and lower regions of the Rio Xingu near the city of Altamira in eastern Brazil. Their native waters are very soft (less than 1 dGH) with pH values around 6.0. They were collected from areas with a lot of leaf litter, overhanging vegetation, and brush piles. There are very few accounts describing the native habitat. Römer reports that he could only get successful spawning at low pH values while others have no problems in neutral water. This could indicate that some forms originate in more acidic conditions.

A. sp. “Xingu” aquarium care

Apistogramma xingu is a great aquarium fish. They are not too aggressive as long as they are provided with a complex habitat. A. xingu are moderately large with males growing to nearly 3″ and females to about 1 3/4″. They need a tank with a complex habitat and will do well in neutral water conditions. Water changes are appreciated and a temperature around 76 F is ideal.

A. sp. “Xingu” are undemanding eaters. They relish live and frozen foods and easily adapt to eating prepared flakes or small pellets. If kept on a sand substrate they happily sift through the sand for tiny particles of food.

Breeding A. sp. “Xingu”

In my experience, these fish form a fairly strong pair bond and work well together to raise the fry. I’ve had spawns of more than 100 but 40 – 50 is more typical. For the best results provide them with a good habitat, frequent water changes, and plenty of high-quality food. I found them to be easy to breed in water with low hardness and a pH range from 5.5 to 6.5.

Give them a choice of breeding locations and the female will make her selection. When she is ready, she’ll lead the make to the spawning site and will lay her bright red eggs which the male will fertilize. After the spawning is completed the female cares for the eggs which hatch to larval fry in 2-3 days. after another week or so the female will lead her babies out to meet the world.

It’s not unusual for the male to share parental duties with the female. Often he will be a full and active partner. The fry grow quickly but it is very difficult to tell males and females apart until they reach maturity. Like most Apistos, A. sp. “Xingu” can have highly skewed sex ratios and a spawn might produce all males or all females. Studies conducted by Römer suggest that a more balanced sex ratio can be obtained if the fry are raised at 78° F for the first 6 – 8 weeks of development.

Where to buy A. sp. “Xingu”

Apistogramma xingu is a little-known species from a group of fish that is poorly understood. If you ever have the opportunity to obtain these fish you’ll find them a great addition to a community aquarium or a species tank. Unfortunately, it’s highly unlikely that you’ll ever find them offered for sale. I don’t know of any wild imports since the 1990s and there is concern that the completion of the Boa Vista Dam has flooded their habitat. However, no one seems to know for sure.

When I first obtained the species I decided to try and maintain them on a permanent basis. I intentionally never selected fish for outstanding color to try and keep the strain as close to wild as possible. There was never much of a market for them but I distributed hundreds over about a decade or so. I was still maintaining them until 2009 when a serious myxobacteria outbreak in my fish room killed all of them (along with nearly 1,000 other Apistos!). That was more than 20 years ago and I can’t know for sure that I would still be maintaining them but I would have liked to try.