FAQs on Genus Callichthys
Related Articles: Callichthyid Catfishes, Summer loving: cats in the garden, kittens in
the kitchen by Neale Monks,
FAQs on: Callichthyids 1, Callichthyids 2,
FAQs on: Callichthyid
Reproduction, Catfish: Identification, Behavior, Compatibility, Selection, Systems, Feeding, Disease, Reproduction,
Corydoras Keep Dying 12/12/18
Long time reader, first time writer. :)
I have a 40 gallon breeder that can't seem to keep cories alive. I've
lost small batches of sterbai (5) and bronze (6), and now I'm afraid I'm
going down the same road with pandas (started with 12, down to 10).
Other fish seem unaffected, and a common symptom appears to be air/gas
Am I missing something?
40 gallon breeder, 36" x 18" footprint, black blasting sand substrate
(well rinsed), temp was at 79-80 for the sterbai/bronze, close to 76-77
for the pandas.
I have a cascade 700 canister filter and 2 sponge filters.
Livestock at this time includes the 10 pandas and 2 Apisto borellii
(1-1.5"). Nothing else.
Some hardy plants, a few driftwoods, and some IAL and oak leaves.
<Whence came the pieces of driftwood? If purchased, are you quite sure
these are "aquarium safe?" Many sold for reptiles are not safe for
aquariums. If acquired from the great outdoors, how did you cure/prep
the pieces? At this point in your story, I suspect the driftwood, but I
will read on...>
Started the tank in mid Sept, with half a dozen small pentazona barbs.
Cycled tank with media from another filter.
On Halloween, I added 5x 1" sterbai cories. The following Friday (2 days
later), in the afternoon, 2 were floating upside down, then 2 more
shortly after. Those 4 died within hours, 1 survived.
<Yikes! Something is seriously wrong here. How did you introduce them to
the system? Did you acclimate them to the new water conditions? Did you
test the water from the pet fish shop?>
I know everyone reaches for sbd in situations like this, but I autopsied
3 of the dead fish,
and the intestines were full of air.
<Well, yeah! There is this thing that happens after an organism dies.
The resident bacteria have a blitz and produce gases as they ravenously
digest their now deceased host. It will happen to you too some day, and
Some food (not much), but intestines were full like those long balloons
clowns make shapes from. No other symptoms.
<...that you could see or recognize with the "naked eye.">
Granted, they're small fish, and seeing anything can be hard.
<If you intend to continue filleting your deceased pet fish, I highly
recommend investing in a good microscope. Much to be seen can't be seen
The lone survivor (which also had buoyancy issues, but never to the
point of floating/dying) was quarantined for 4-5 days (no meds, since no
<A good policy>
and seemed to stabilize. But 3d after being returned to the main tank,
it also died,
and again it appeared full of air. I should note that the autopsies were
done shortly after death, and all of the sick fish were very buoyant
before they died
<This can happen for any number of reasons. It is a very non-specific
symptom - a sure indicator of poor fish health, but with a lengthy
(i.e. I don't believe the gas in intestines was a post-mortem symptom).
<Impossible to know for sure either way.>
Through all this, the pentazonas were fine. Ammo/nitrite were 0,
nitrates were 5-10.
On Nov 6 I added half doz bronze cories (I admit to getting them as coal
mine canaries; clearly this tank can support fish, but can it support
cories?). All 6 died one by one over a 2-3 week period. No outward
symptoms (well, except dying). Frustrating. And they had started off so
well in my tank, foraging deep in the sand, very active. These did not
float when they died.
Through all this the pentazonas were fine. Again, parameters good.
I rehomed the pentazonas to a new office tank, and the tank stayed empty
for about a week.
Then on Dec 4 I got a dozen 0.75-1" panda cories, added them, along with
a M/F Apisto borellii.
<That is a lot of fish to add all at once.>
They seem to be great tank mates, same pace, feeding rate, temperament
All has been good until last night (Dec 11), when 1 was floating (air in
intestines again), and another this am (didn't check). As of Sunday when
I did a whack of testing, parameters generally good; ammonia was over
<Yeah mate, I think you added too much too quickly to a "dormant"
but under 0.25 (I've been feeding liberally, though, so that might be
<Yes, that too will do it. I would stop feeding for a few days at
I dosed with Prime, haven't re-checked yet), zero nitrites, nitrates
<Prime is a one-time "band-aid" type fix. It binds the nitrogen cycle
products so that these get taken up in the filter. If you don't keep
adding it, the problem will return unless corrected some other way.>
I feed good quality food, and lots of variety. Thawed bloodworm, mysis
shrimplets, bbs. Crushed Spirulina flake, regular community flake,
Hikari mini wafers, Fluval bug bites.
<Maybe too much though?>
My tap water is moderately hard, so I have been mixing the water for
this tank with RO/DI at about 3:2 (RO: tap). That's giving me dGH of 5-6
(100ppm), and dKH of ~4 (~75ppm). My pH remains around 7.5 (hard to
tell, since it always appears to lie right between the high end of the
normal pH test, and the low end of the high range pH test).
I'm using a perpetual drip and overflow to keep new water running
through tank, rate of about 1.5g new water per day. And I vac as
<As necessary? How often is that?>
Why do mid level fish appear to remain healthy and fine, while bottom
dwelling cories are dying?
<Very different species have very different sensitivities, ability to
tolerate physical and/or physiological insults. I suspect the problem
here to be either trauma from transport/introduction or a toxin coming
somewhere as of yet unknown. Do see other similar recent queries here:
Are there any diseases/infections/conditions that are known to cause gas
in the intestines as a primary symptom, i.e. not post-mortem?
<Again, floating and bloating is just too common a symptom - like
headaches and nausea in humans - could be from anything!>
Any suggested interventions? Shelled peas? Epsom salt in tank, or as
<Do read other query answers in the link above. I suggest removing the
driftwood, adding carbon, looking for other potential sources of
toxins... also be sure to follow good acclimation protocol.>
Many thanks for your time and consideration!
<Cheers Sara L>
Re: Cories keep dying 12/14/18
So fast with the reply, thank you!!
You've focused in on a few things I did not think are important, and
aren't placing much weight on things I've been clinging to. Which is why
I have asked the experts!
<Haha, wait, who told you we are experts?>
To put me straight, so to speak. :)
The driftwood: 1 large piece, collected from a local headwater stream
(no ag runoff or pollutants).
<Yeah, right... that you know of or that has been reported/documented.>
There are brook trout in this stream (maybe other tiny fish?). The wood
was allowed to dry for about 6 weeks, then boiled for 20 min.s. In any
event, I'm more than happy to remove all possible problems,
<I do strongly suggest you remove the piece collected locally. It's just
too much of an unknown and a likely source of something troublesome.
Even if it is not a toxin from runoff/pollutants per se, there could be
something else (some tannins maybe) leaching out of it.>
and work from there, so I'll pull it out tonight. There are also a
couple of smaller pieces I got from a local aquascaper, vine wood he
imported by the crate, and it's used in many tanks by many local
<If removal of the large local piece doesn't solve the problem, I would
remove smaller ones these next.>
Carbon: Great suggestion, I missed that. It will go in tonight.
<Never really hurts and often helps!>
Acclimation: floated sealed bag for 20 min.s, then add small amounts of
tank water over 1hr (pour out half of mixed water half way through),
then add fish to tank via net
<Nets are terrible (too much risk of injury with them getting
stuck/tangled). Personally, I avoid them whenever possible. In my
opinion, it's better to scoop them out gently by hand than with a net,
or just pour them out with the last little bit of bag water.>
without any store water. But deaths have all occurred after at least 2
days, and now upwards of a week - is that consistent with insufficient
<Based on the technique you described, no, I doubt acclimation was the
problem. As for how injury from poor acclimation might manifest in the
fish, that can vary greatly.>
I've never found an answer to this.
Store water: not tested, but I believe it has similar pH and hardness to
this tank. Regionally, our water is quite similar from one municipality
to another (medium hard, well buffered). It's definitely not polar
Dormant tank: during the week the tank was dormant (before I added the
12 pandas and 2 Apistos), I kept feeding the tank with crushed flake
(using the same amount as I had been feeding when it had fish).
Adding too many fish: In my own defence, the tank/filter was still
cycled when I added the fish, the cories and Apistos are all very small,
and for the bioload, it's a big tank. I haven't been testing daily, but
none of the fish (past or current) showed any signs of irritation/stress
like gasping, flashing, hiding, pumping gills, and so on.
Vac "as necessary": I keep my tanks pretty clean. Most have sand
substrates, which require less maint than gravel. I vac when there is
visible detritus in areas with less flow. At any rate, I never go more
2 weeks between vacs, and "water changes" are constant with the drip
Prime for low ammonia reading: I know this is a 24-48hr band aid, and if
the source of ammonia, or lack of processing ability aren't addressed,
the problem persists.
Rate of feeding: I'm generally conservative when feeding my tanks, but I
have a soft spot (fear spot) for new fish. Cories are such casual
feeders, I'm fearful that the 30 second or 2 minute rule won't give
<Do reduce your feeding. Fish do not need as much food as people tend to
think they do. Also, they can go a very long time (we're talking weeks)
without any food at all.>
Even with the filter off, some foods don't even settle to the bottom in
that time. When I listed all the foods I feed, I should be clear that
it's not all at once. One at a time only. For flakes or other dry food,
smaller-than-medium thumb-and-one-finger pinch is all. For frozen foods,
less than half a cube of bloodworm, or maybe a quarter of a portion of
mysis. At any rate, I'll fast the tank for 48hrs, dial back the feeding
after that, and monitor ammonia carefully.
<I think if you remove the drift wood and add carbon, you will likely
see an increase in your Cory survival rate.>
<Good luck! - SaraL>
Re: Cories keep dying 12/14/18
Thanks again, Sara. Driftwood out. Carbon in. No food. I'll keep an eye
<Great. Do start feeding again in a couple of days though. :-)>
Also of note: Like many fish folk, I rarely test except when something
is wrong (that I can see or sense). But with this tank, I've been
keeping on top of parameters a bit more diligently, given the problems
<It's always a good idea to test every once in awhile, problems or no
I mentioned in a prior email that I am seeing trace ammonia. I've had a
chance to check other tanks and tap water, and I'm getting a trace
reading across the board. Best match for colors is between <0.25ppm for
tap and other tanks, and >0.25ppm for the Cory tank. Even my RO/DI is
testing at >0ppm. So I'll look into an ammonia removing media for the
filter, and continue to use Prime and monitor.
<Sounds like a reasonable plan.>
<Cheers, Sara L>
transporting Corys 6/28/16
albino Cory barbell loss, going for air
Good morning WWM crew!
Thanks for your helpful website and advice.
I'm plotting the introduction of some Cory Trilineatus to my tank and
have come across information about their ability to secrete poison
during stress. Apparently this can sometimes kill them during transport
to their new home? I will only need to take them a short distance so
they'll only be in the car for about 20 minutes, then of course the
period. Do you have any suggestions for minimizing the chances of this
sort of poisoning?
<Ah yes; the addition, blending of your system water in small amounts (a
quarter or so of the shipping volume) every ten minutes or so; then
discarding the mixed water, moving the cats (by hand if it were me/mine;
to prevent tangling pectoral and dorsal fin spines in a/the net>
<Welcome. Bob Fenner>
My name is Gabby and I'm new to aquariums (had one since August) and loving
it.i've slowly built a community tank (doing lots of research) since then and
it's gone quite well.
I have a question about my albino Cory. I have a group of four and
yesterday saw that the smallest one had lost his barbels. Today, I've seen him
go up for air quite a bit, much more than the others. He's still quite
active, but during feeding seems to have eaten less than the others. Should I
just keep monitoring him? Any suggestions?
<Catfish lose their barbels for two reasons. Or rather, there are two things
going on that interact, resulting in the barbels getting shorter.
Keeping Corydoras catfish in tanks with gravel (especially sharp gravel) rather
than sand causes the barbels to get damaged. Very fine (sometimes called "pea")
gravel is better than regular aquarium gravel, but the best
substrate is silica sand (a lime-free sand, sometimes called "pool filter" or
"smooth silver" sand). What happens is the barbels get damaged, and that's when
the second part of the process, bacterial infection, sets in.
The bacteria cause the tissue of the barbel to die back, and over time the
barbels get shorter and shorter. Improving filtration and water flow along the
bottom level of the tank can help. Some filters (especially small
internal canisters and hang-on-the-back designs) often don't "suck" much water
from the bottom and the outflow is very much directed along the top of the tank.
This means the lower half of the tank suffers from low oxygen
levels, which causes catfish and loaches to swim up and gulp air. Note that
under optimal conditions Corydoras rarely gulp air -- they're very much
"facultative air-breathers" meaning they only breathe air when forced to do
so. That's unlike Bettas which are "obligate air-breathers" meaning they will
suffocate if they can't breathe air because their gills are proportionally
smaller than they should be (in the wild, Bettas live in places where the water
doesn't hold much oxygen, so relying on their gills alone would be pointless).
Anyway, under better conditions the barbels grow back very quickly, and on
healthy Corydoras you'd be surprised how long they get, not far off half an
I also have a question about his lost barbells. When I decided on Corys, I
decided on sand. The guy at the aquarium shop told me coral sand works, but now
I'm wondering if it's the cause of his barbell loss.
<Coral Sand was a terrible choice. Bad advice from the retailer there!
Coral Sand is made of limestone. It's from the sea, basically mashed up
seashells and corals. It makes the water hard and alkaline (i.e., raises the
amount of minerals in the water as well as raising the pH). Over time, this
stresses most freshwater fish. (Not all: livebearers and Rift Valley cichlids
LOVE coral sand because it creates conditions they want. But Amazonian and
Southeast Asian fish come from soft, acidic habitats and they aren't going to do
well in tanks with lime-rich sands.>
The other three and their barbels are fine. Is this sand too rough?
Any thoughts or recommendations would be much appreciated. This little school is
rivaling my Betta for favourite status, and I want to make sure they are healthy
<For sure a fun group of fish, the genus Corydoras.>
Thanks in advance,
<Most welcome, Neale.>
Re: albino Cory barbel loss, going for air
Thank you for your quick response! I'll go out and look for silica sand right
<Cool. Aquarium shops sell it, but it's often cheaper at garden centres.
Just clean it well, or you'll make the tank really cloudy.>
What would you suggest to increase oxygen flow at the bottom of the tank? I have
a hang off filter.
<If all else fails, an airstone weighted down so it draws water up from the
bottom of the tank (that's what the air bubbles do) to the top of the tank.
Cheap and cheerful. Alternatively, there are all sorts of small pumps called
powerheads that do the same thing electrically. Finally, you could buy a small
internal canister filter and place it somewhere at the bottom of the tank, maybe
hidden behind some rocks or plants, and let it push the water around.>
Man, so much to learn still!
<Part of the fun of the hobby is the learning. Corydoras are easy fish, and very
reliable for beginners, but there are one two issues with them. Would direct you
to this page:
Various links at the top that will take you to interesting/relevant articles.
Stocking question + catfish ID
<And gals Rhiannon; how's it?>
I have a stocking question for you. I have a badly stocked 3ft
(150litre) tank - I have 3 clown loaches, 4 angel fish, 6 rummy noses, 6
phantom glass fish, a Bristlenose Pleco and a black widow tetra. I'm
looking to upgrade to a 6ft tank to remedy this. I'll move the loaches
and at least 2 of the angels to the 6ft.
I came across an amazing deal on a 2nd hand 6ft tank
(1830x460x600) on eBay with all the bells and whistles - but
the issue is that it comes with fish and I was hoping for an unstocked
tank so I could have free choice.
I asked for some clarification on the species in the tank. The owner
doesn't know much about what type of fish they are so they sent me some
photos and here's what I've worked out.
- 3 clown loaches
- 1 black ghost knife fish
- 1 Bala shark
- 2 gouramis (one female three spot, one female silver)
- Unspecified number Siamese algae eating fish
- 2 catfish (unknown species)
I'm pretty ignorant about catfish, so I've attached the photo of that
Would you guys be able to tell me what species that is?
<Mmm, yes. Is a Callichthys species, an armored cat of the same family
as the popular Corydoras>
All the owner could tell me was that it was a catfish and a "monster" -
apparently they have been growing very quickly.
<A peaceful animal as you'll find out>
I'm okay with some of the species (the loaches are great because I'd
wanted to get at least two more to rectify the social issues going on
with my three), iffy on others. I wanted to check with you guys - are
there any serious alarm bells here? I get the impression that this tank
may be fully stocked as is as most of these species get rather large --
is there any room for the new additions?
<Yes... the Bala may be skittish as a solo specimen... jump out over
time... the Black Ghost Knife could get quite large here and possibly
pick on its smaller tankmates... but there's room for more>
Thanks in advance,
<Welcome, Bob Fenner>
Seeking info about Callichthys 12/14/08 Hi
there! I am back with yet another question, I hope it's not too
much trouble. The LFS in my area is going out of business,
unfortunately. They are sticking around for Christmas, and then they
are calling it quits. Naturally, I was in there shopping for deals...
In with their goldfish was what I initially thought was a porthole
catfish, but after Googling around believe to be Callichthys
callichthys. (It was simply labeled "armored catfish", which
could mean anything!) It looks similar to the fish in the link below:
It was a dull olive green/grey color, so possibly a female? I believe
this fish is also known by the common name Cascadura ("hard
shell" in Spanish). Does anyone know anything about this fish, or
know of a place to find more information? I can't seem to find much
about them in my books, and the online information I have found has
been spotty. Some websites say they get to 5" long while others
say 8" or even 10" - and the acceptable tank size starts as
low as 15 gallons, which I am certain can't be right. I have an
unoccupied 29 gallon tank that I was going to turn into a brackish tank
for guppies and platies, which might work out if this is indeed a
brackish tolerant species. (We're only talking about 1.003-1.005
SG.) I imagine this catfish would keep the fry in check, which is fine
by me! If I knew he would outgrow the tank, I could take my time
finding him a more spacious home. Does this sound like an ill advised
plan, or could it work? I never rescue fish from pet stores, because I
know this only encourages them to restock. However, since the store is
folding, I thought "just this once..." since I doubt anyone
around here will appreciate a catfish like this. Thanks so much for any
help! Happy holidays to you all, Nicole <Hi Nicole. The Porthole
Catfish is typically Dianema longibarbis, a smallish (10 cm), midwater
schooling catfish closely related to Corydoras. It's named after
the row of roundish black blobs along the midline of the body, like
portholes on a ship. It's a pretty good community tank catfish. Not
a brackish water species, but otherwise adaptable. Now, Callichthys
callichthys (the Cascarudo) is quite a different beast. It's quite
a bit bigger (up to 20 cm) and unlike Dianema doesn't really swim
about in midwater and prefers to slither about on the substrate between
making mad dashes to the surface to gulp air. It's body is largely
unmarked, but the pectoral fin spines have a distinctive orangey
colour. It has tiny eyes! Callichthys callichthys is incredibly tough,
and will tolerate slightly brackish conditions (around SG 1.003)
without much bother. Hoplosternum littorale is a bit more of a brackish
water specialist, and would be my recommendation for life with guppies
and mollies. But there's not much difference between the two fish
otherwise. Both species are boisterous, semi-aggressive at feeding
time, but otherwise good community fish. Cheers, Neale.>
Re: Seeking info about Callichthys 12/14/08 Hi Neale, Thank
you very much for your comments. I don't know why initially I
thought it was Dianema longibarbis, definitely no "portholes"
since the body was overall drab with no markings. I guess the barbels
looked similar, and I only had a vague memory of what a porthole
catfish looked like from a TFH article I read last year. I can't
remember seeing any orange, so maybe it was Hoplosternum littorale
instead of a Cascarudo? (Thank you for giving me the correct spelling,
that improved my hits considerably!) I'll look more closely
today... <Hoplosternum (and its sister genera Megalechis and
Lepthoplosternum, both of which contain former Hoplosternum species)
are generally quite easy to tell apart from Callichthys. If you look at
the head of Callichthys species, you'll see that the eyes are very
small. It also has a basically square tail fin. By contrast,
Hoplosternum has normal sized eyes and a deeply-forked, V-shaped tail
fin. Maintenance of all these species is very similar, except to say
that Hoplosternum littorale at least favours hard water, and quite
possibly brackish water, in the wild, and consequently does not do
especially well in soft/acid conditions. By the way, the orange
pectoral spines on Callichthys callichthys are only obvious on adults,
and I believe just the males at that.> I guess I will go ahead and
get the catfish, and plan on putting an ad in the online classifieds
next year, to see if I can't secure him a more spacious home. Right
now he/she is just under 4" or so. The only thing that troubles me
is that everything I've read says these are schooling fish, to be
kept in groups of five or so. Would a singleton be exceedingly unhappy?
(He/she is already alone in the tank.) <Singletons of all these
catfish (they're very closely related) do just fine on their own,
provided they're not combined with anything overtly aggressive.>
I could get some Brochis splendens, if that would help, and move away
from the slightly salty concept and choose different fish altogether.
<Brochis are superb catfish, and tolerant of a range of conditions,
though again, I'd not put them forward as obvious candidates for a
brackish water aquarium. Hoplosternum and Callichthys spp. catfish do
occur in brackish water, so would make better choices. Hoplosternum
littorale at least has a tolerance for up to 40% seawater salinity!
Given it's closely related to Corydoras, it might be quite a
surprise to many people that this species favours brackish water
habitats in the wild.> As you can see, I am already feeling
attached...I think it's the tiny eyes that I find so endearing!
Maybe because of being very nearsighted myself. <Sounds very much
like Callichthys! Yes, these are probably "legally blind"
catfish, but they don't seem in the least put out by that. When
settled in, they are goldfish-like in their pushy feeding time
behaviour, and become very good pets. They used to be common in the
trade, but from the 80s onwards much scarcer as people switched to
smaller or more colourful tropical fish. Callichthys are hardy, do well
at subtropical as well as tropical temperatures, and will eat just
about anything, so are really very versatile fish.> Thanks so much,
once again. Nicole
<Happy to help, Neale.>