The knifefish you actually want, Xenomystus nigri

[@dixsigns1717]

Becca thank you!

[@adieaf61]

how refreshing to see a real tank, rather than something 'poshed up' for a video. Thank you.

[@Thomas.Saunders]

Enjoyed the detailed information.

[@FreshwaterIchthyology]

Thank you!

[@TheZenGinger]

What cool fish! I don't think I've seen those before! Thanks for sharing! 🤗

[@FreshwaterIchthyology]

They used to be really popular and in a lot of stores but I guess black ghosts, A. albifrons took over even if a lot larger and less social. Such a shame as really nice fishes.

[@TheZenGinger]

@FreshwaterIchthyology I still see the black ghost knives everywhere and occasionally the clowns, but those are just really neat looking and seem so much more outwardly social in general! 🤗

[@FreshwaterIchthyology]

Same with black ghosts but less clowns, I think these are the only Z. nigri around for a long drive as no one else seems to stock them. These can be illusive but happy with much smaller fishes like normal tetra, but do come out much more.

[@TheZenGinger]

@FreshwaterIchthyology I'm not sure if they were "Kerri"/"Royal" tetras, but the colors on those was just gorgeous! Some almost looked somehow red and blue in different lighting, and I was highly distracted by them as well! Lol

[@FreshwaterIchthyology]

I think they are but one doesn't look much like them, I just got really confused and left them to it haha. I swear my original kerri I had obvious males but one of my current lot looks like a normal emprour.

[@TheGreatOceanDisasterAquariums]

I had them years ago and loved them. They are so sociable, friendly, curious and active. They used to be available all the time but I have not seen them in the trade for years. I never realized they were related to morymids. I also had several Gnathonemus petersii years ago as well after getting in a bunch of 10" specimens when I used to buy fish to wholesale. That was the only time they came in that size.

[@FreshwaterIchthyology]

I agree, I only started keeping them after the popularity and it's such a shame as they are lovely fishes. I've never managed to own Mormyrids, all that are available are either too territorial or too large. Never seen G. petersii even wild fishes that big, wow!

[@stevenbisset8717]

cool fish , bet live daphnia would see different fish .

[@FreshwaterIchthyology]

I bet they would love it, I might get different live foods for them. They really like frozen foods.

[@gibbberishh]

Great video! Really put these little guys in my mind for a future species tank - one question though is that you mentioned a standard size of around 15-20cm but fishbase has a max at around 30cm (admittedly from a field guide 20 years ago so hard to verify) which makes a big difference in whether a tank is appropriate for them. So do you think that's just an outlier and that they're usually much smaller or do you think they can all grow to that length given enough time?

[@FreshwaterIchthyology]

Fishbase does make strange statements and are often uncited and if they are the references don’t always back them up. I’ve certainly never seen a specimen that large. I can double check the original description. Field guides can be a little hit and miss and unless it has photos of the fish they are measuring it could not even be that species. It’s a bit like some sources claim 50cm SL Gnathostomus petersi but there seems to be no sources of fishes that big.

[@gibbberishh]

​@@FreshwaterIchthyology Thankyou for the response! Indeed it seems like there's a few reports of "maximum size in the wild" in oddball fish which often don't match up with the experience of aquarists

[@FreshwaterIchthyology]

The literature only suggests 20cm but the original description says 15cm. Günther, A. 1868 (14 Mar.) [ref. 1990] See ref. at BHL Catalogue of the fishes in the British Museum. Catalogue of the Physostomi, containing the families Heteropygii, Cyprinidae, Gonorhynchidae, Hyodontidae, Osteoglossidae, Clupeidae,... [thru]... Halosauridae, in the collection of the British Museum. v. 7: i-xx + 1-512