RTC won't digest and won't throw up?

[Viktor Jarikov]

I lost a ~12" RTC recently due to a new problem I have never encountered before. Autopsy showed he did not digest the food - most of the chunks of fish he so voraciously had eaten just two days ago were still in his stomach but now partly rotten. Why did he not digest or at least regurgitate? I haven't a clue.

I thought it was a freak accident but started paying close attention to his 10" brother living in the same tank. He tried to do the same thing 2 weeks later - had fed hungrily one night and then in two days his belly still had a bulge and he was breathing heavily and sometimes would make sudden, jerky movements with his mouth/gills. Thinking he was gonna follow the fate of his mate, I took him out and placed into a large salad bowl with tank water. I stuck a finger inside his stomach, which was surprisingly easy to do but could not feel much definitive. His tummy was very soft, as if fluids built up around it. Not being able to stick two fingers inside, I didn't know what to do and was afraid to stick twizzers inside his stomach for fear of injury. So I kept sticking my finger in his stomach every 30 sec and eventually he spit out several chunks of half-digested meal as of two days ago. These didn't smell half-rotten like the ones out of the first RTC did.

I guess lots of water entered his tummy when I was sticking my finger in and out and it helped to throw up.

This fella was ready to feed a little that night but I didn't give him anything. Two days later he was feeding like nothing happened. That was two days ago. Will see now.

Any thoughts, related experiences? It strikes me as highly strange. Goldfish are known to have a lazy intestinal system in high nitrate water (one of the causes of goldfish floating syndrom). But my water is good. My other fish eat the same food and are fine.

[Viktor Jarikov]

Second attempt.

[Scleropages]

Victor, what are the water parameters in the tank with the RTC(s) you are talking about?

[Redtailrob]

Hello Victor.

Lost a small P.Lutkeni/zungaro zungaro to a similar issue a few months back.
Feed him as normal with a small chunk of white fish & other a period of about a week he swelled up like a ballon & past away
All water parameters good & showed no external signs of illness, redness, raised scales, fraying whiskers, anything.
With regards to you RTC Ive had something similar with mine in that he ate & then swelled up quite dramatically a few days after the meal.
I ceased all feeding for a period of 2 weeks, increased the temperature of the water to aid digestion & also increased the aeration to make up for the increase in temperature, eventually all swelling subsided & the fish became active again.

As an alternative to the procedure youre carrying out an alternative wouldn be to try & feed your RTC a piece of thick animal fat, the thick edge of a large steak for example. Catfish struggle to digest large amounts of animal fat and will usually try and regurgitate the meal along with the remainder of its stomach contents.
Be prepaired to do sevaral large water changes if it does so.
Personally I wouldnt be sticking my fingers down the throat of the fish as this would be very stressful.

[Viktor Jarikov]

Victor, what are the water parameters in the tank with the RTC(s) you are talking about?

NH3 0
NO2 0
NO3 20 ppm
pH 6.5
Temp 75 F
Hardness low, no #

fresh liquid API test kit

Rob, Thanks much. I see similarities, so these things do happen to others. Albeit, mine never got swollen, just looked like the food never left the stomach.

Update Dec 28 2011.

The remaining RTC got back to normal for ~10 days and then started to breath heavily and jerk with his mouth and gills. So did also a new RTC 14". The other two fish in the tank, a 15" TSNxLeiarius hybrid and a 14" Zungaro zungaro, have been normal throughout this whole ordeal. The new RTC has been feeding quite sluggishly despite having been rehomed a month ago. The original 10" RTC feeds voraciously when feeling good.

This is maybe 4th bout of heavy breathing and poor appetite (while the other two fish appear fine). Sometimes my 75% WC helps but other times it doesn't or they improve on their own.

Still don't know why. I think I am going to fast them for 1-2 weeks and then give them food soaked in anti-parasitic meds, as I don't know what else to do.

After 3 years in the hobby and having kept around 100 different fish species (90% cats), I am becoming more and more convinced of my RTC curse. Never, ever do I have so many problems and deaths as with other fish species, COMBINED!

With every new RTC problem, I am developing more and more respect for people like Taksan who managed to keep two RTCs for 27 years.

[Scleropages]

In my opinion, you are keeping the temp too low. As long as you have enough aeration and water movement, you would do well to keep it at 80-82 deg F. Digestive enzymes in any animal need a specific temperature range in which to work well. I'll bet the issue you're speaking of isn't solely due to temp, but it can be a stressor.

Also, what are you feeding your RTCs?

[Viktor Jarikov]

Good logical thinking. But Cat-eLog lists Temperature for RTCs at 21.0-26.0°C or 69.8-78.8°F. Now, these guys did spend 1/2 year in a pond outside at average temps of ~85 F where they grew from 2" to the current 10"-14". What you say, makes me wonder if their digestive systems are having troubles adjusting to the lower temps. The temp change was not abrupt by any means. It is directly related to the local weather as I employ no heating or cooling of my tanks and ponds, just shading when I have to.

This all has been happening in Naples, FL. When I had my RTCs in Rochester, on average the water was significantly cooler, averaging at about 72-74 F year round in my basement pond (4500 gal) and 75-77 F in my tanks in the house. As I said, I had problems with RTCs then too, more so than with any other fishes. Different symptoms though.

I feed them the same as always: chunks of fish, mostly lean marine and sometimes fresh water, occasional shrimp, dry catfish pellets. When I give them big chunks, they have the most problems. Small pieces, thin slices cause far less problems.

When they were in the pond, they, I am sure, supplemented their diet with local guppies that are numerous in all my ponds. That's why I had thought of parasites. But that is a weak hypothesis atm.

[Scleropages]

The foods you are feeding them seem to be okay. I wonder, though, if your RTCs would benefit from less fish flesh and more shrimp, whole fish, pellets, etc. Something with more texture or fiber than just fish flesh. Of course, a close friend of mine has had a RTC for over 15 years now and he feeds it anything and everything.

One thing that comes to mind with tanks/ponds without a heater is the amount the temperature can vary between night and day. I have no idea what this variation is in your ponds/tanks, but it could also be enough of a stressor to cause digestive issues in your RTCs. I'm not sure if you have a digital thermometer that records max and min temp, but if you do, you can study the temperature variation in the tank/pond in question. That might shed more light on a possible stressor.

I empathize with you. You obviously have the space requirements for RTCs but don't seem to be having the greatest luck with 'em. I hope the situation can be righted.

[Viktor Jarikov]

Hey, thanks again. When I said fish chunks, I literally meant it - cut up whole fishes. When they eat shrimp, they appear to digest it faster and easier but I am not made of money to feed them shrimp. They do get plenty of roughage to sweep their tummies clean as should be.

S: Of course, a close friend of mine has had a RTC for over 15 years now and he feeds it anything and everything.
VJ: very impressive. Your friend must have fine-tuned the conditions by now. At over 4', I am sure, it does eat anything. You just never know. There are people, like that guy in London who runs a big fish rescue or the guy Ted in Seattle who builds outdoor tropical ponds, who make hot-dogs (chicken or turkey) a staple for their RTCs and others and their fish thrive. There are cases like me who tries to be as careful as possible and fail.

S: One thing that comes to mind with tanks/ponds without a heater is the amount the temperature can vary between night and day.
VJ: the temp variation is rather small, ~1-2 F inside and ~2-3 F outside. It is indeed something I keep track of, being of anal nature.

S: ...but don't seem to be having the greatest luck with 'em.
VJ: thanks for trying to downplay it but it feels, atm, as a real curse.

[Viktor Jarikov]

The last two RTCs died. They stopped eating ~2 weeks ago. Were breathing quite heavily and made jerky sudden movements often. Treatment with the usual gram-positive antibacterial meds - nitrofurazone and furazolidone - didn't change anything. Neither did my usual anti-parasite combo of metronidazole+praziquantel. The other two tanks mates - TSN-Leiarius hybrid and Zungaro zungaro have been fine throughout this time.

I cut them up just to find nice, clean insides. Nothing suspicious whatsoever to a visual exam. Black slime on the gills at death - reminiscent of some of my first RTC problems - http://www.planetcatfish.com/forum/view ... lit=+slime

So I am back to being RTC-less... yet again. I can't believe it atm. I've lost about 7 sub-adult RTCs throughout 2 years in Rochester, either to strange bacterial infections, unresponsive to meds, or to them swallowing inedible objects (~50%/50%). So, I had thought, I learned now and eventually got 7 RTC babies at 2"...

Not the greatest luck, you say? It's a down right disaster.

[wrasse]

But Cat-eLog lists Temperature for RTCs at 21.0-26.0°C or 69.8-78.8°F

Victor I think you are right to highlight the catelog temp... 69.8 sounds extreme at the low end, to me. It may well have been recorded in the locale, but it would soon recover?

I don't have capacity to keep a big fish like an RTC, but if I did I would keep it at 80-82degF, perhaps dropping it to 76-78 for a few months, but no lower. That's just my view. Spending too long at too low a temp would weaken the immune and digestive systems of the fish.

During the previous Winter, didn't Florida get snow? In your unheated aquaria and ponds, how did your fish cope with that plunge in temperature?

[Viktor Jarikov]

Thanks, Wrasse. I have little idea how these temp ranges come about here or at the FishBase.

What you say can be taken as a hypothesis to be tested (I like it)... still, then, it remains to be explained why I have had no such problems whatsoever with a bunch of other tropical fishes, including plenty of those that co-inhabit with the RTCs in the wild - TSNs, Leiariuses, Zungaros, and other large pims, Doradids, etc. - to mention the most relevant ones.

Last time it snowed in Naples/Ft. Myers/SW FL area was in 1977, I am told. 2" of snow.

Last year there, indeed, was a cold spell for 7-10 days of 30-35 F nights and 50-55 F days - that's when we were house-shopping here and bought our FL house. The worst this winter (our 1st FL winter) produced has been 2 days of 34-40 F nights and ~60 F days. I did have to apply tank heaters, increase the well water flow to the max (74 F), and cover my ponds with layers of tarps and blankets, because the greenhouse/exhibit area is not finished yet. The pond water's been steady at 70 F. I reduced the feeding. Everyone seems happy atm, though.

Usually, it is ~55 F daily min and 75-80 F daily max.

As a reminder, the three last RTCs, I lost, lived inside the house in my 120 gal tank. They've never seen water temps below 72 F (72 F was rare, mostly below 75 F).

[Jools]

69.8 sounds extreme at the low end, to me. It may well have been recorded in the locale, but it would soon recover?

It's a tricky one but I agree it could be misleading. It's down to the massive range of this species. Perhaps and updated entry in the catelog could explain that a bit more. However, I doubt anyone reading it would go, OK, let's keep this fish all the time at 70F. I think.

Jools

[Viktor Jarikov]

The more I think about it, the more I find "the temp effect" an agreeable hypothesis.

It'd be helpful, I imagine, to hear from the "successful" RTC keepers out there: what temp do you keep your RTCs at?

Just a few data points would hardly be conclusive but it'd be better than nothing. If we had good poll numbers and they pointed to 79 F or higher, then it'd be good new knowledge because Cat-eLog implies that RTCs should not be kept all the time at or above 79 F (or does it not imply that??).

I'll start a new thread on this, then, since it is a somewhat different topic... and in hopes of a better response: http://www.planetcatfish.com/forum/view ... =7&t=35007

[Viktor Jarikov]

Update July 1 2013.

Well, after 1.5 years, I think I have a better understanding what was wrong with that 120 gal. Simply put, I underestimate time and time again how much water movement is needed. I've been burned by this many times before - when will stupid me ever learn? I am pretty sure that the problems I had with the RTCs' deaths in the tank and similar but non-fatal (removed them to a pond just in time) problems with a Jau and a TSNxLeiarius hybrid were related to low dissolved oxygen.

A few weeks ago, I got a pair of North Thailand tiger datnoids and they suffered greatly as if suffocating, although their tankmates 2 juruense cats, 1 irwini, 2 ripsaws, Distichodus sexfasciatum, 2 spiny eels, 1 RTC, and 1 L. marmoratus appeared fine. I took them back to the store and they recovered. The discussion with the most-helpful owner led to the suspicion that "just bubblers and no filter" is not enough water agitation. So I added two pumps and 3 more airstones and got the dats back and now they have been fine. (During the crisis, I've searched and searched the net but failed to find a mention that dats would be more sensitive to oxygen than many/most other fish...)

The surprising thing is that neither the cats nor the dats ever showed me it was oxygen-related by going/staying close to the surface. They all hung on the bottom. On top of that, I've raised two juruense cats, 6 irwinis, and 5 silver aros from small babies in that tank without much of a problem - always ate fine and digested fine, never showing any sign of distress.

Anyhow, that's my story and I am sticking to it. There is no other viable explanation I can offer and the foregoing cannot be just a coincidence in all likelyhood.

Here are my poor dats struggling to breath: