what tankmates for Cephalosilurus apurensis?

[Viktor Jarikov, posts: 2317]

I just got a 10-12" specimen from RiverWonders. Nice-looking cat! For now he/she is sitting in the cage inside my indoor pond adjusting.

Questions:

(1) Cat-eLog: "Sexing: Females larger and much more aggressive, very distinguishable dimorphism by venting especially at larger sizes."
--- what does this mean? I mean how do I sex mine?

(2) Cat-eLog: "Feeding: ....Aside being controversial from an ethical perspective, it risks introducing parasites and other potential diseases."
--- what's the controversy?
--- the second statement goes for ANY fish, so what is Cat-eLog trying to say??? does this say this fish runs a HIGHER than usual risk of introducing parasites/diseases? (if so, that should be stated clearer) Why? Eating habits? Are they tr or wc?

VJ EDIT: a-ah, this is about feeding live feeders to this cat. It would help if the "it" in the second part of the sentence was replaced with what it is, i.e., "...., feeding live fish risks introducing....."

(3) Cat-eLog: "Compatibility: Very aggressive and not shy. One aquarist reports their large female has attempted to eat 10'' cichlids with death coming to the cichlid by suffocation. Although unable to swallow them she would hold them by their entire head to the gill plates until they expired and would continue holding on even while the fish was being yanked from her!"

Cat-eLog: "Suggested Tankmates Best kept alone or in the most bullish of considerably larger company. "

--- Would he/she try to eat 8-10" sorubim lima, marbled pim, ID shark, marbled bullhead, RTC, TSN in a 2500 gal pond (as opposed to say a 200 gal aquarium)?
--- If yes, I will have to drop it in the other pond section behind a divider BUT I have 2 alligator gars ~1.5-2' TL and one very aggressive TSN ~2' in there. The section is ~6' long of the 25x6x3' pond viewtopic.php?f=25&t=29488

[Viktor Jarikov, posts: 2317]

Shane's world article: "Sex differences. On the subject of sexual dimorphism in Cephalosilurus, there is no firm information. As far as our animals are concerned, on the basis of the entirely oblong and blunted form of the genital papilla, are obviously the same sex and males. Some suggest the fact that - as with Lophiosilurus alexandri - adult females are larger and in the front third of the body are broader and brawnier than males. Additionally, at least with C. apurensis, we can report differences in behaviour – the female is more aggressive. Again concerning the reproduction in Cephalosilurus, we have no knowledge; thus far they have not been captive bred. Since the catfish live solitary lives, a male pairing with a larger and stronger female may only be tolerated for a defined time period and only for the purpose of the mating in its area."

[Viktor Jarikov, posts: 2317]

from the same source: Growth and final size. Every now and then one reads that C. apurensis is a species that, at least compared to other predatory catfish, grows rather slowly. We cannot confirm this. In their first, and also strongest, growth phase our specimens in only three months carried out jumps of 12 to 18, 16 to 25 and 20 to 28 centimetres. After a length of 30 centimetres, growth slows down somewhat, the 40-centimetres mark is reached after a further ten to twelve months. Our largest animal clearly exceeded a total length of 45 centimetres. From this size C. apurensis is adds more to its girth than to its length, bet even then length growth has not yet stopped. So is to be assumed when fed well, the animals can grow up in the aquarium slowly and constantly to around 65 centimetres of length in a decade. According to Japanese sources, even lengths of 70 centimetres and over are possible.

Why does Cat-eLog give only 11.8" as a max size??

[Richard B, posts: 6338]

According to Japanese sources, even lengths of 70 centimetres and over are possible.
Why does Cat-eLog give only 11.8" as a max size??

Cat-e-log is based on firm evidence of a size, like a photo with a scale - it can be increased as long as there is firm evidence cat-e-log is incorrect - can the japanese sources provide firm evidence? Also measurement are in SL so tail is ommitted from this measurement.

I have seen these kept with success with a number of species ...BUT they must be of equal length & of a robust body proportion - ie - no skinny sorobim shaped fishes & they must be well fed. I have also seen these fish harrassed in the confines of large tanks where no suitable cover is provided (by a festae, i think it was). Success with tankmates can be a bit trial & error but can be influenced by available territory, feeding regime etc.

Remember that an analagy would be keeping a bear, a tiger, a lion, a puma, a wolf, a wolverine & a leopard in a large barn - they don't all live together in the wild so interactions cannot always be predicted even if they are well fed with their own personal spaces - any tank or pond is always gonna be way smaller than what they'd be in, in the wild so keepers need to give consideration to how we look after our charges

[MatsP]

Since this seems to be more about "bugs" in the Cat-eLog than about the fish itself, I'm moving it to the appropriate section.

Later on I will action the things I think should be dealt with (e.g. the "it" replace with "live fish").

Edit: I decided to move this BACK to SA catfishes (Everything else).

--
Mats

[MatsP]

As far as size is concerned, they grow to at least 300mm/12" standard length. Many people use total length when sizing fish. Of course, the tail isn't same length as the fish in this species, so if anyone can show a fish with a standard length greater than 300mm, I'd be happy to extend the size in the Cat-eLog. I have this discussion with one or another member every few months. I have so far altered less than three species based on this sort of discussion [not counting typos or other mistakes/misunderstandings - e.g. the Hypostomus that was said to be 35mm long, when it should have been 350 according to several sources].

The size we use is the "best available at the time". I have CLOFFSCA (Checklist of Freshwater Fishes of South and Central America), which is not a book I would generally recommend - but for keeping the list of species in the Cat-eLog upto date, it's very useful, because most species listed in CLOFFSCA have a size. Fishbase is another source of this sort of information. When adding new species that are recently described, I use the description size, unless other verified information is available.

Sexing: Venting is when you hold the fish with the ventral side up [or hold it high in the air] to see what the "bottom" of the fish looks like. The article you quote seem to say that the male has a blunt "penis" bit, but I'm not sure what to look for on a female. If you have two fish, you should be able to tell if they are the same or not. And most catfish can be sexed the same way as Corydoras: Females are bigger, mainly "wider" over the mid-region. This works on nearly all species of catfish - although there are of course quite a few exceptions too - in many Loricariidae, the female is the larger one.

--
Mats

[yellowcat, posts: 60]

Having kept c. fowleri, c. apurensis and several other pseudopimelodids I can offer some experiences. I raised a c. apurensis from 5" in length to over 20" in length in the span of about 2 years. Raised originally on live feeder goldfish I was able to wean it off them to live nightcrawlers and frozen silversides plus chunks of frozen striped bass, tilapia and various saltwater market fish.
Mine was always kept alone as I'd read about enough keepers losing prized tankmates. As others have suggested the can probably be kept with fish larger than themselves and even then must be kept well fed. I know this is true regarding my c. fowleri that shares a tank with several other catfish species for what it's worth.
I recently sold the apurensis as it out grew the confines of it's 60G bowfront tank. If not kept alone, never try to mix c. apurensis or c. fowleri with their own kind, each other or any other pseudopimelodid species as they won't get along at all. My specimen was a female.
Here's some pic's of my former apurensis.....

[Viktor Jarikov, posts: 2317]

Cat-e-log is based on firm evidence of a size, like a photo with a scale - it can be increased as long as there is firm evidence cat-e-log is incorrect - can the japanese sources provide firm evidence? Also measurement are in SL so tail is ommitted from this measurement.

Thank you Richard! Appreciate your help, as always. BTW, festae is likely as mean as fish get Yet, as for the size thing, with all due respect, you appear to select the info you can (apparently rightfully) discredit, like the mention of "Japanese sources stating 70 cm" but you omit the credible info from a published journal article that is also featured on this site in Shane's world (which supposedly validates it even further?) that states that the article owners DID have a >45 cm specimen and firmly state that these fish do grow to 65 cm over a decade - that's over 2 feet!

Also, see Yellowcat's comment below - his apurensis grew to over 20" in 2 years. Even if he means TL, which I hope he will clarify, subtracting the tail length will give you quite a bit more than 11.8" for sure. Do we need more evidence? Richard? Mats?

Mats, thanx for realizing this is much more about substance and less about bugs and thanx for planning to act on my little "brain fart" I apparently experienced when reading the Feeding section. Still, worth rewording more clearly. My 1st proposal "feeding live fish" is also ambiguous because the predator being fed is a live fish too. "Using live feeder fish" may be the clearest wording.

Also, thank you for explaining venting. It lacks the "r" letter as in ventral, so I did not get it. In technical, verbal and informal situations, venting means letting vapors/gases out, releasing pressure, blow off excess pressure, etc., which makes for a funny interpretation of the Sexing section in Cat-eLog. Or maybe it's my warped sense of humor....

Yellowcat! I hoped you'd chime in as I noted your name in the keepers lists Thank you for the info and pics. Will attach mine. Wow, she was pretty! You probably felt sad parting with her. Yeah, the article in Shane's world is also VERY CLEAR: cephalosiluruses do not mix!

Summary: so the big section of the pond with some big and smallish 8-12" cats is out of the question for he will hurt/eat the smallish ones. This leaves only the section with the two 1.5-2' alligator gars and the aggressive 2' TSN. Now, again, despite the mentions of some experiences, I still lack a clear answer:
(1) it is highly unlikely c. apurensis can hurt the gars and the TSN, right?
(2) so the only worry is can they hurt him??

[Viktor Jarikov, posts: 2317]

Mine was always kept alone as I'd read about enough keepers losing prized tankmates. As others have suggested the can probably be kept with fish larger than themselves and even then must be kept well fed. I know this is true regarding my c. fowleri that shares a tank with several other catfish species for what it's worth.

that's worth a lot - that was 50% important in the first post and now became a 100% important question.

[Viktor Jarikov, posts: 2317]

Here are the pics of the current prisoner and the "monsters" lurking outside of his cage - the two alligator gars and the TSN:
can he join them and be safe????????

[Viktor Jarikov, posts: 2317]

3 more

[Viktor Jarikov, posts: 2317]

1 more

[Birger]

Thank you Richard! Appreciate your help, as always. Yet, as for the size thing, with all due respect, you appear to select the info you can (apparently rightfully) discredit, like the mention of "Japanese sources stating 70 cm" but you omit the credible info from a published journal article that is also featured on this site in Shane's world (which supposedly validates it even further?) that states that the article owners DID have a >45 cm specimen and firmly state that these fish do grow to 65 cm over a decade - that's over 2 feet!

I do not think Richard is out to discredit anyone...but just pointing out we need proof...sometimes it is as simple as something just needs to be noticed...and now that it has been brought to our attention (thank you) that there is a possibility the Cat-eLog is incorrect it can be looked into, time permitting. The Cat-eLog is a work in progress.

If you would like to put together some details (as you are doing already) and send it to one of us it would save some time as well.

That is a good looking beast you have there

Birger

[Viktor Jarikov, posts: 2317]

As you see from the pics, he cannot even completely stretch out in his prison-5 gal-bucket, unless he assumes an angled or vertical position. I feel bad for him but better safe than sorry... Him and I would appreciate prompt concrete helpful advising that will decide his housing fate.

[Viktor Jarikov, posts: 2317]

Birger, thanx!!!

Yeah, I know Richard is not out to do that... that's why I used the word "appear" for he addressed the easily discredible info and was mysteriously silent as for the solid info... perhaps just his time was not all that I want

[MatsP]

The size issue is really a case of "until someone clearly states that they have measured the fish, and preferably provide evidence" [at least for fish that do have a size in the Cat-eLog from a reliable source].

I've had far too many posts saying "my fish is X long", and when you say "Really, I didn't know they grew that big, how did you measure it", it turns out they didn't measure it, they were just estimating. Case in point:
viewtopic.php?f=13&t=30220

First post says the fish is 8cm.
Then in another post:

well i did not measure it exactly, it's a rough guess. I measured today with a cm outside the aquarium so not really exact but i measured about 5 centimeters including the tail. My eye is indeed too big... The ancistrus is a little bit bigger.

The error here is about 3/8 or 35%.

And this is not the only time I've experienced this. A lot of people do this [and that includes some of my guestimates of sizes of fish].

--
Mats

[Viktor Jarikov, posts: 2317]

sure thing Mats! As you well aware, I am one of the over-over-over-estimators remember my post "a pair of 3 foot channel cats, are they not?" ? viewtopic.php?f=13&t=29628 they really turned out to be 25" and 27", not 36", albeit I never gave it any small effort or even a small thought to measure them - just went from an impression while working with them all day long, which says it all about me and my big eyes, I guess...

yep, your case in point is very fresh, I remember it...

not to tire you out by repeating it over and over, but the 45 cm/65 cm measures are in a reputable published (peer-reviewed?) scientific paper and on this website already, so in my mind, it is not anymore about anybody coming forth and saying yes I measured it and here is the number and the evidence but it is all about someone taking a look at the real paper or the one recited on PC (although I copied and pasted the relevant paragraph) and improving the Cat-eLog; still I understand and appreciate your efforts to edify me for the future

[MatsP]

So is to be assumed when fed well, the animals can grow up in the aquarium slowly and constantly to around 65 centimetres of length in a decade. According to Japanese sources, even lengths of 70 centimetres and over are possible.

The bold is mine. It is not a measurement, it is an assumption. So whilst we all agree these fish may well grow larger than 30cm SL, there is no real number that I feel confident to put into the field...

--
Mats

[yellowcat, posts: 60]

To confirm a couple of points, I measured my c. apurensis throughout it's time here and at the time of it's sale last month it was slightly over 20" total length and by all accounts still growing, I estimated it's weight at around 5lbs. A reputable importer friend reports raising one to the length of 28" which weighed 18lbs! I should mention that when consulting my "my cats" page I realized I'd kept the fish for 2 years, 10 months. Having read Wolfgang Ros' accounts of keeping cephalosilurus I can very much agree and confirm his experiences with mine. For what it's worth, the cat-e-log states that c. fowleri grow larger than c. apurensis and reach a length of 15.9 " but I'm inclined to disagree. I have a female c. fowleri that I've kept for 5 years, 3 months and it stopped growing a few years ago and is 13" long but then it's only one specimen of course. I should mention that I acquired my apurensis at my lfs but they got it from RiverWonders as well. I hated to sell the fish, she was my fave and I took a big loss moneywise but selling it was in the best interest of the fish... More pic's including a birds eye view on sale day...

[Richard B, posts: 6338]

Been at a conference, so offline for a bit...

I've seen a 20" specimen but i have no proof!!! People who know me may well take my word but others may say "rubbish"& want proof - i do not have it - for purposes of consistency the site will take measures where there is evidence available.

Supposedly some very reliable people (who others i trust implicitly will vouch for) have seen brochis at 7" long but no photo exists....shame , whatta fish that'd be.....

I'm not out to discredit anyone but in this day & age even the worlds worst pic would add credibility - shame if no pic exists but i believe the Jap source is accurate: however Jools may ant a bit more before cat-e-log is updated...?