What is this mystery fish?

[DoubleDutch]

It's the same if you had a Puntius something, you'd say I have 1 puntius or I have half a dozen puntius. It's just in the case of cories the full common name is also the scientific name, whereas you'd actually say I have a barb rather than

It's the same if you had a Puntius something, you'd say I have 1 puntius or I have half a dozen puntius. It's just in the case of cories the full common name is also the scientific name, whereas you'd actually say I have a barb rather than a puntius.

In Latin the plural of Puntius would be Puntii hahahaha

 

[Byron]

An explanation may help to fathom this more; I happen to be fascinated by scientific nomenclature, but those uninterested can skip this post.

The scientific name (genus and species) is the last and most specific in the hierarchy of scientific classification. The genus is part of a Family, and the Family belongs to a certain Order; for our purposes, we do not need to go higher than the Order. The Family and Order can each be further divided into “Super” and “Sub” families and orders. Each of these terms includes “clades” or clusters of fish that are phylogenetically related. Phylogeny is sometimes referred to as the natural relationships and is an attempt to construct the history of all life based on the evidence from both living and fossil organisms. When classifications are based on phylogenies we can ascertain (and predict) how that group of related fish function, and since this tells us something about their behaviours and requirements it is of interest to aquarists. The "name" of a species includes the genus and the species epithet; every living organism has only one unique and internationally recognized scientific name.

A binomial nomenclature system is used to name all life, botanical and zoological; simply put, “nomenclature” means the names along with the system used to assign those names, and “binomial” means two names. These two are the genus (plural genera) and the species (or specific epithet). This system was developed by a Swedish botanist, zoologist and physician named Carl Linnaeus who lived from 1707-1778. In 1735, Linnaeus published his Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis; in translation, “System of nature through the three kingdoms of nature, according to classes, orders, genera and species, with [generic] characters, [specific] differences, synonyms, places.” Usually referred to as simply Systema naturae, by the thirteenth edition in 1767 it had become a monumental classification of all then-known species of life on earth. The system further developed into modern Linnaean taxonomy, the hierarchically-organized biological classification that is today used to classify all species of animals and plants. Strict rules govern this system, established and enforced by the International Code of Zoological Nomenclature [ICZN].

The genus name is either Greek or Latin, but most often Greek, and is always capitalized; it is singular and plural, and like all Greek and Latin it will be male or female gender. The species epithet is always Latinized and is never capitalized. The genus and species are in italics, followed by the name of the original describer of that species and the year in which it was named in standard uppercase. For example, Carnegiella marthae MEYERS 1927 tells us that this fish, the black-winged hatchetfish, was first described and named by Dr. George Meyers in 1927. When the describer and date are in parentheses, as for the Black Phantom Tetra Hyphessobrycon megalopterus (EIGENMANN, 1915), it indicates that the species is no longer in the genus to which this species was first assigned. In this example, Eigenmann originally placed this fish in the genus Megalamphodus but Stanley Weitzman and Lisa Palmer determined that the fish actually shares certain phylogenetic characteristics with the other species in the rosy tetra clade within the Hyphessobrycon genus, and in 1997 they published their findings and re-assigned the species to Hyphessobrycon. But as Eigenmann was the first to describe this fish as a new and distinct species, his choice of the species name remains valid and his own name as the describer is placed in parentheses.

 

[RoseRed]

Synodontis nigriventris. It really needs to be in a group of its own kind. They live in shoals of hundreds in nature.

That could be it. It looks like it is upside down because the spikes/whiskers seem to come from the wrong place.
The place that I get my fish from is a very small shop, in a small rural town, and I don't recall seeing them sell this particular breed at all. So I'm wondering if he has stowed away right from her suppliers, to her, and then to me.

 

[Stanv03]

I'm not sure how long I have had this mystery fish as he only comes out of hiding on very rare occasions, but the first time I saw him was a few months ago. When I saw him, I was like "What the heck is that?"
To me he kind of looks like what you might get if you bred a yoyo loach with a bristle-nose catfish (both of those types of fish are fish that I DO have in my tank).
Anyway I will post a video of the fish in question. Don't worry about the audio as that is just TV right near me. I also apologise that the video probably isn't the best as he lives in a boat towards one end of the tank and unfortunately there is a cat tower on the wall near where the tank is, so I can't really squeeze in between the two very easily.
But anyway, he is the fish seen coming out of the ship at the 3 second mark.

This is an upside down catfish. I have 2 of them in my 55 with my Acara. Half of the time they’ll swim normally but other times they’ll swim upsidedown

 

[Byron]

Agree on the species being Synodontis nigriventris. Being a shoaling species, a group of 3-4 (or more) is advisable to avoid additional stress. If this individual fish was "accidental" it may be very difficult to find more. Not much you can do about that. It does sometimes seem to enjoy the company of Corydoras fish, though they are not at all closely related notwithstanding some obvious similarities including the pectoral fin spine that can be locked into position; the first ray of the dorsal fin is also a spine.

Synodontis belong to the Mochokidae, a family in the Siluriformes order, which currently has nine genera with approximately 200 described species, all occurring in Africa. The fish in the Corydoradinae family of the Siluriformes are endemic to the Americas, and none occur in Africa. It seems plausible that the two families evolved distinctly after the breakup of the two continents.

The genus Synodontis was erected by G. Cuvier in 1816 (originally as a sub-genus of Pimelodus), and the genus name derives from the Greek syn [= together] and odontos [= tooth] in reference to the closely-spaced lower jaw teeth [though there is some dissention on this derivation]. The species epithet is Latin and literally means dark belly, and refers to the reversed counter-shading.