Pterosturisoma microps

Order: Siluriformes
Suborder: Loricarioidei
Family: Loricariidae
Subfamily: Loricariinae
Genus: Pterosturisoma
Species: Pterosturisoma microps, Eigenmann & Allen, 1942

Ptersosturisoma microps is a slender built fish with a long tail and filaments on the pectorals and the caudal fin. It can grow up to 20 cm but reaches a bigger length with its long filaments. The body surface is covered in plates which are not spikey or rough. It has really small eyes, like its species name allready tells (micro = small, ops = eyes).

The overall coloration is a dark grey/brown to black. The caudal fin and filaments can be brighter and when damaged turn white. Between the scales are bright borders visible, especially on the underside and overall when being stressed.

Pterosturisoma microps is a very dificult to keep fish, since it is sensible to big changes in water parameters and stress. New added animals often don't eat very well and tend to starve if the necessary food or water parameters are not given. Since this fish dies rather quick in captivity, breeding didn't happen often and as good as all animals in the hobby are wild catches.

This fish prefers to be in small groups and mostly searches its own kind in the tank to sit together in the current of the streaming pump. It is a totally non agressive and non territorial fish, which prefers to sit on wood or glass above the ground. The substrate on the ground is mostly only visited for eating. Newly added P. microps have to learn to eat from the ground, which can take some time. Once aclimatized this fish is totally not shy and eats also next to bigger and more dominant fish.

Even though P. microps moves mostly via its mouth over the surface its sucked on, it can also swim good in open water. Its stiff body movements with the spread dorsal fin remind a little on the swimming behaviour of sharks.

P. microps is found in Peru. There it lives in the Amazon River in the area of Iquitos. Its habitat consists of fast streaming water with lots of driftwood and branches in it. P. microps prefers to sit with its head faced to the current sucked on a piece of wood or branch.

Soft and sligthly acidic water and temperatures of 26 - 30 °C are found in its habitat.

This species is mainly herbivorous and is often observed scratching on algae. Other than algae, it seems P. microps also grazes on surfaces covered with bacterial slime. In it mostly a lot of micro-organisms can be found, which are also eaten. In general this species prefers to eat above the substrate and therefore eats mostly algae or bacteria growths that are flat enough for the animal to not loose its suction on the surface its sitting on while eating.

When P. microps is kept at home it is really important to observe if it eats well. It takes mostly some days, till this fish even starts to eat or gets used to processed food. Most specimens come into the hobby in quite bad condition with a fallen in belly but a healthy P. microps should always show a full belly which should never look concave.
This species normally searches for food the whole day and is busy eating growths off surfaces. This is a difficult thing to simulate in the aquarium, without spoiling the water to much, with uneaten food remains.

We made good experiences with first offering them pastes or tabs that can be sticked to the glass. That way the animals can search for the food above the ground, where they sit anyhow all day long. If the food is positioned in front of the streaming pump, the animals will locate it fast over the smell. We suggest to try a lot of different food sorts to see what is taken good. Especially after putting them into a new tank, the animals are mostly so stressed, that they need more energy to manage the acclimatization.

With these food sorts we had the best success so far:
- Plankton paste (especially in the beginning)
- Dr. Bassleer Biofish food Chlorella, Green and Garlic
- Spirulina tabs (all time favorite)
- Frosted artemia
- Snail soft granulate
- Microbe lift vita pleco (is smelled by the fish really fast)
- Zucchini (especially when it starts to get more soft after some days)

It is said that P. microps can also be fed with white yoghurt mixed with spirulina, which should help to build up darm flora. This mixture is spread on a flat stone and dried before it is put into the tank. We didn't try that so far.

It should be taken care, that P. microps is not only being fed plant based food, since in its natural diet it also takes in micro-organisms like little insects and crustaceans.

To check if P. microps eats good, its easiest to look at the poop of it. If it poops homogeneous, dark strings, without slime, the fish eats food in a healthy way. This is especially important because it can sometimes take weeks till a concave belly looks healthy again.

Once the fish are used to the given food, they don't seem to be shy anymore and are greedy eaters and mostly first ones at the food. Not even more dominant fish can scare them away.

Pterosturisoma microps is a middle sized fish which needs an aquarium of at least 120 cm length.

The aquarium should be structured with a lot of driftwood and branches, for the animals to sit on. Most of the time you will see them sitting on the place with the strongest current. As substrate fine sand can be used but doesn't play a big role in keeping this species.

It is important to get enough flow and oxygen into the tank. This is best accomplished with a strong streaming pump and an air stone. Next to that a good filtration and an internal heater should be installed. This fish is day active and not scared of bright light, which means a daily rhythm of 12h light a day should be applied.

Weekly water changes of at least 50% should be mandatory, more are very welcomed by the fish. They are not so sensitive to the pH and temperature as long as it is consistent and acclimatization was done in a good way. In general soft water with a pH of 6,5 - 7 is optimal as a temperature of 26 - 30 °C.

It should be taken care not to put this species together with fish who damage their fins and filaments. We had this experience with Nannacara adoketa, which than didn't stay long in the aquarium. Other than that, a lot of tetras and barbs can be interested in the thin filaments of P. microps. It is best to keep them together with more substrate bound fish, like plecos or sand dwelling Loricaria. Especially in the beginning it should be taken care, that P. microps gets enough food. This species enjoys being in little groups of 3 - 6 specimens of its kind.

Sexing Pterosturisoma microps can be a very hard task, since there is not much info about it to read as also almost no breeding reports about them. We have to admit that we had our dificulties with it also and had the luck to speak with some experts about it, to figure out the exact sexing traits of this species.

When we look at the animals from the side, the first thing we notice is the hight difference. The male looks more massive and in general higher than the female. The brighter coloration of the male is only indicated by stress, which is not a sexing trait.

We also see some differences, when we look to the side of the heads. Males seem to have a bigger head, where the eyes look comparably smaller.

A look to the pectoral fins sadly doesn't reveal much with this species.

From top things start to be a little bit easier to judge. The male shows a broader body figure, especially in the back end of the body.

The head is for us a really good indicator for sexing this species, since the male shows it bigger, more robust and broader as the female.

The tails from top look quite different. The male shows it far broader than the female.

The most famous sexing trait always seemed to be the naked area above the papilla. It is often mentioned that male and female show this area different shaped, where the one shows it in the form of a star and the other one more like a trapezoid. This seems to be not an sexing indicator, since females with reported spawns showed this area shaped in different ways. What is a better sexing trait is the papilla itself. The male shows a broad, oval, white area around the papilla, with a small and slender papilla in it. The female shows a white and round area totally filled with its round and bigger papilla.

Also visible from underneath are the pelvic fins which seem to be slightly longer at the male and shows a thicker hard ray.

If you compare the heads from underneath, also there is a difference visible. The female shows a more pointy head with less border around the mouth. The male shows the head more round but with strong borders, which lets the mouth look smaller compared to the head.

Pterosturisoma microps is a substrate spawner which prefers to lay eggs on smooth, clean, vertical surfaces. Before spawning this surfaces gets cleaned by both male and female. This substrate can be stones or wood in the wild. The male takes care of the eggs, till the fry hatch.

In captivity this species has only been bred a few times. Mostly triggered by bigger water changes, the breeding pair spawns on the tank glass or a substrate where the streaming pump blows the fresh water against.  Sadly we have not more information about water parameters or how to raise the fry.