Rare and unheard of aquarium fish species

I'm searching for rare and unique fish species in the hobby. Not because I intend to keep them, but because it just interests me. However, searching for fish species that are mostly unheard is not very easy. Hours of research and I can maybe come up with one new fish. So what fish species do you know of that only a small handful of hobbyists have heard of or had the chance to keep?

 

Sumo loach comes to mind (not to be confused with dojo loach). They were introduced to the aquarium trade only a few years ago. I came across them in an LFS and couldn't pass them up. Unfortunately, with how limited the info on them is, I learned that they are small tropical community tank assassins and rehomed them. They were incredibly hardy. A lot of people contacted me wanting them, but none of them had ever heard of sumo loaches before.

 

Sumo loach comes to mind (not to be confused with dojo loach). They were introduced to the aquarium trade only a few years ago. I came across them in an LFS and couldn't pass them up. Unfortunately, with how limited the info on them is, I learned that they are small tropical community tank assassins and rehomed them. They were incredibly hardy. A lot of people contacted me wanting them, but none of them had ever heard of sumo loaches before.

What do you mean by assassins? They just kill everything?

 

Sumo loach comes to mind (not to be confused with dojo loach). They were introduced to the aquarium trade only a few years ago. I came across them in an LFS and couldn't pass them up. Unfortunately, with how limited the info on them is, I learned that they are small tropical community tank assassins and rehomed them.

Pity, I googled them and they're gorgeous! And cute, wouln't have suspected them to be agressive .

 

What do you mean by assassins? They just kill everything?

They were very quiet, infrequent killers. I never saw them being aggressive so it took me a long time to figure out why I had just one fish die at a time every couple weeks from what appeared to be another fish attack. Then I pieced it together, removed them, and things stopped dying.

They also hid for so long that I actually thought they had died! They burrowed into the substrate below some rocks and I didn't see them for three months. Then they came flying out, plump and healthy as could be, when I was moving around the rocks one day. My guess is they're very nocturnal.

Pity, I googled them and they're gorgeous! And cute, wouln't have suspected them to be agressive .

When I got them, they were being housed with goldfish. I think they would do exceptionally well in a community setup so long as it didn't include small tropicals. The guy I ended up selling them to added them to a cichlid tank and he had no problems.

 

Research "Dawkinsia Mascara Barbs". Very uncommon & expensive.
I keep Dawkinsia Filamentosa Barbs, close cousins to the Mascaras.
I'd likely sell my African cichlids if I could find & afford a large group of Mascara Barbs.

 

my local fish store had Piorski's tetra. never seen them before. appears fairly new to the hobby. nice looking small tetra

 

Shadow catfish they are not to rare but have not heard of em tell yesterday when I saw them at my LFS

 

I saw some clown catfish, Gagata dolichonema, for sale recently. I hadn't seen them before, and I couldn't find much information on them either.

 

Recently found out what I had bought earlier this week.
It's new to me and the people at the fish store didn't have much about it either.

Sicydium plumieri

 

My all-time favorite fish:
Hemirhamphodon tengah

I'm fortunate because there is a specialist aquarium shop (Utaka) here in the Netherlands that mostly imports wild fish and often has rare ones. Even though it's a Dutch site, you might be interested in looking at their stock lists, which change regularly (especially now, during the Covid crisis). They have videos next to many of the fish names. They have very rare fish quite often.

Anyway, I was there one time and saw the Tengahs and fell instantly in love! They look to me like Gonzo of the Muppets. As comical as they are, they are also very beautiful, with irridescent jewel-like bodies. They are not easy to keep. I had to feed them small live foods by dropping them onto the surface of the water. Eventually, they became tame enough to recognize me and would take an offering from a pincet. They are surface dwellers and, unlike halfbeaks, they are not aggressive and they are also egg-layers. Their water requirements are also different from that of others in their family.
They never bred for me, which was a disappointment. I kept them with a school of wild Boraras Brigittae and Boraras Merah and red Sakura shrimp.
Everyone of themexcept for one was gobbled up by damsel fly larvae, which had sneaked into my tank with some introduced plants (Even though I had quarantined the plants first!) Unfortunately, a few months later, my remaining fish panicked when I moved too suddenly outside the tank and he crashed into the glass. It knocked him out and he swirled down to the bottom, but regained consciousness. I thought he'd had a narrow escape, but the following day, he died. I had been unable to get him new tankmates because the fish were no longer available. I found a video, which I'm going to try to link here:

I forgot to mention how tiny they are: 4 - 6 cm. You can see photos if you google "Hemirhamphodon tengah" images.

 

A few days ago my LFS had green kuhli loaches for sale... not sure how rare those are but I’d never heard of them before, they were pretty cool!

 

Maybe the Loaches were dyed or genetically enhanced like glofish.

 

I'm searching for rare and unique fish species in the hobby. Not because I intend to keep them, but because it just interests me. However, searching for fish species that are mostly unheard is not very easy. Hours of research and I can maybe come up with one new fish. So what fish species do you know of that only a small handful of hobbyists have heard of or had the chance to keep?

I have a borneo python eel. This particular breed is more newly discovered and can be difficult to get your hands on.