Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

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Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

Post by N0body Of The Goat »

Back in September 2012, I purchased a ~3cm SL baby C. ornatus, who quickly reached ~20cm SL within two years. This specimen is now pretty close to fully grown, at least ~23cm SL.

Yesterday, I purchased a ~16cm C. ornatus at the Association Of Aquarists auction, who has one had one functional eye since the previously owner bought the specimen from a fish store ~12 months ago. This catfish is currently in a quarantine tank, not just for health reasons, but ensure it adapts to the food I offer my fish (my bigger specimen readily eats New Era pellets squashed into balls) and hopefully grows a little before I can make an introduction.

These catfish are supposed to shoal in the wild, but my big fear is introducing them to each other in a month or so and the smaller one being thought of as lunch by my larger one.
My larger specimen has never knowingly eaten a live fish, the balls of squashed pellets are less than 2cm diameter, but when it yawns that mouth is a ~6cm diameter chasm... Definitely greater than the diameter of the smaller one currently, if taken tail first!

Has anyone here introduced C. ornatus to each other when they are no longer babies?
How big a difference is size was there?
Did they recognise one another as being conspecifics and play nicely together right from the start?
I presume the best plan of action after quarantine would be to place smaller one in a new tank and then add the larger one?
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Re: Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

Post by fat meloe! »

Although I am not experienced with catfishes, you could try using a glass divider to separate them (but allow eye contact) and carefully watching the big fish's reaction to the small one. I got this idea from a story in Herbert Axelrod's Exotic Marine Fishes book, in which a pike and some perches were divided like this in a public aquarium and the pike showed predation behavior.

Hopefully a more knowledgeable aquarist can comment on my idea?
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Re: Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

Post by Viktor Jarikov »

I have a short description of the experience with my trio on page 14, ~mid page, here http://www.planetcatfish.com/forum/view ... &start=260

They do indeed have a huge mouth, my guys could swallow a 1' koi easily with that mouth yet they have never gone after even a 3" koi. It baffles me why they need such a whale of a mouth when they appear to be so utterly non-predatory. They too prefer pellets to thawed fish, etc.

They indeed appear to have an affinity for each other and like staying close most of the time but not always. Sometimes they spar a bit too and even engage in the mouth-locked-on-mouth battles. But this shoving is not too vicious, I think just a pecking order sorting out.

Of course, mine grew up together and have always been about the same size. It's a gamble and I may be a lot less careless than most aquarists but if it was me, I'd introduce them together and watch closely, so perhaps making first acquaintance early morning on Sat so you have the whole weekend to keep an eye on the situation.

A temporary divider can be also be a good solution to see what'd happen across the divider, if anything, except it needs not be transparent as catfish perceive their environment by taste mostly while indeed pikes and perches do so by sight.
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Re: Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

Post by Jools »

Another thing I'd mention is I've never seen a catfish eat another fish tail first, always head first.

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Re: Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

Post by N0body Of The Goat »

Thanks for the input so far!

It seems my biggest challenge might be to get this new Chrysichthys eating dried food, namely New Era pellets squashed into a ball, like my other one raised from a baby. I've offered a fresh ball the last two nights and neither appear to have been eaten, so were syphoned out during daily ~25% water changes.

I'm slightly concerned that this new fish likes lying partially on its right side, while inside the plastic cave it came with. Maybe this is somehow related to which eye is functional and which is not (I couldn't say right now which is the damaged eye without disturbing the fish)?

It also has another quirk of sometimes slowly swimming "on the spot" inside the cave, something my elder Chrysichthys does not do (he/she is very sedentary). Maybe this is related to the current supplied from the Eheim Biopower 240 (~1000lph less inefficiencies) in what I think is a ~75l quarantine tank?

They do seem rather an odd species, with such predatory reputations and that huge mouth that can form a ~6cm diameter circle, yet at the same time my elder one was very placid (besides the odd time when it bit the tail of my Auchenoglanis from the side and the time I saw it lash out and miss a ~15cm SL Euchilichthys in a large clay pipe, which is what prompted to move it out of my 6-foot community two years ago).
Part of me is so tempted to add them both back to the 6-foot community this summer, to live with my...
1x Distichodus cf. rostratus
6x Distichodus cf. affinis
1x Synodontis notatus
1x Syndontis cf. budgetti
1x Auchenoglanis spp. (not sure on ID these days, but grew to ~30cm SL under two years from ~4cm SL and not sure if it grown longer since)

Which then means moving a few fish out of the 6-footer...
3x Ctenopoma acutirostre (although at ~13cm SL, they might be safe)
2x Hypseleotris compressa
1x Xenomystus nigri
3x Synodontis brichardi
1x Synodontis schoutedeni
4x Euchlichthys spp. (one royauxi and three guntheri, possibly)

Most of the fish that would need to be removed could easily be put into other tanks, with a bit of juggling, but it's that quartet of Euchilichthys that concerns me a lot. I get the impression very few keep these fish in multiples, in a 6-foot tank they can spread out (with just the odd "fireworks" fight for a second before they go their separate ways), but I worry about their conspecific aggression in a 4-foot tank.

Jools, that's a good point about how fish eat, attacking from the tail end means the prey could swim away. Not so easy if your head is inside the predator's mouth!
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Re: Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

Post by Birger »

All you can do is put them together and see what happens. As always 2 is a bad number one will chase the other.
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Re: Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

Post by Viktor Jarikov »

I like Jool's thought and it may explain the phenomenon. It appears swallowing head first is the preferred way. But not the only way. Many catfish that I observed would swallow other fish, catfish or not, tail first too, or at least attempt to, especially if the tail end is more "swallowable" than the head. Sometimes, the tail half even gets into the stomach and gets half-digested and the leftover is then spit out.

As for feeding thawed whole fish, if the thawed fish fits comfortably in their mouth, my catfish don't seem to care which end goes in first, regardless of the spines. This used to surprise me but I see it all the time. Of course, I try to get them to grab the thawed fish head first but this is not always successful.
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Re: Safely introducing smaller Chrysichthys ornatus to conspecific experiences/advice?

Post by N0body Of The Goat »

Gutted, woken up this morning to find the poor fish dead in quarantine, offered all sorts of food including two live earthworms and one of them has gone back in the garden.:(
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