RTC or Red Tail Catfish at Fish Story Aquariuma and Rescue

[thebiggerthebetter]

This is one of those rare occasions when I witness RTC fighting, even rarer to see two different genders involved. It looks like a hierarchical dispute of two fish in the middle of the hierarchy of 4 specimen. The biggest, the alpha female (7 yo, 4 feet), and the youngest, the beta male (3 yo, 3 feet), are not participating.

It appears the alpha male (7 yo, 3 feet) was challenging the beta female (7 yo, 3.5 ft) and got bitten up significantly over the course of a day or so, a slow-moving fight with many bouts. The female suffered damage too but being bigger and stronger gave more than received. For a while the female wasn't even biting the male and his fins, only pushing, poking with pectoral spines, and body slamming but eventually, he got her riled up by biting her pectoral fins and latching onto them so the female started biting the male back, especially latching onto his tail.

Hurts me deeply to see this but I have no way to separate them, no spare, large enough tank. I never film fights because I proceed to separate the fighters right away but here there was nothing I could do. I am also against fight filming but here the only benefit appears to be educational /awareness raising, because many peers keep multiple RTCs together, and the benefit is to show how these magnificent animals, called the emperors of Amazon, interact with each other sometimes in captivity, likely in too small a tank, albeit I am not sure this would have not occurred in a 10x or 100x bigger tank. As most, I am learning a lot as I go.

 

[fishdance]

Hello V,
This is spawning behaviour, the female is testing the strength of male. Biting and pulling male around by tail is typical. Will message you off-line later. Remind me later if I haven't

 

[fishdance]

How is the tail damage looking?

Be careful of infection/fungus on fins near the base "meat" of tail. There is a large bed of arteries & capillaries that goes right to the tail end / clear finnage. Essential to bring good and oxygen as the tail muscle works so hard. So any infection may send toxins directly to the rest of body & lymphatic system.

Fin damage/fungal & bacterial growth is fine as the fish is tough but infection at the base of tail can be surprisingly deadly.

Dab of Iodine gel or dribble of undiluted acriflavine (when fish is netted out of water) to stain the fungus area will get faster recovery. The damaged finnage may slough off allowing new clean regrowth.

 

[thebiggerthebetter]

This is spawning behaviour, the female is testing the strength of male. Biting and pulling male around by tail is typical...

Interesting. Thank you. Your experience of course dwarfs mine 1000x to 1x, especially in the breeding area, so I'd tend to trust your take. I myself would have never thought this could be gender relations.

Also, territorial and hierarchical catfish's favorite place of attack is the tail fin in general, followed by other fins.

Unless you tell us more of convincing info, I will remain torn whether this was a dominance fight or as you say some kind of rather strange (to ignorant folk like me) gender relation.

As I have observed plenty of breeding and courtship this spring with these exact RTCs (which didn't appear to lead to anything though) and published a video of it (see above), I must state their spring time behavior was very, very different. Pretty much a ton of swimming and circling and gentle nudging by snout, touching and caressing by barbels, male swimming under female and nudging her from below, as I'd describe it.

Nothing like this whatsoever. Hence, I remain convinced, for now, this is not a gender behavior but a dominance dispute fight.

How is the tail damage looking?

Be careful of infection/fungus on fins near the base "meat" of tail. There is a large bed of arteries & capillaries that goes right to the tail end / clear finnage. Essential to bring good and oxygen as the tail muscle works so hard. So any infection may send toxins directly to the rest of body & lymphatic system.

Fin damage/fungal & bacterial growth is fine as the fish is tough but infection at the base of tail can be surprisingly deadly.

Dab of Iodine gel or dribble of undiluted acriflavine (when fish is netted out of water) to stain the fungus area will get faster recovery. The damaged finnage may slough off allowing new clean regrowth.

Thank you for this great and edifying info. The RTCs look alright. No inflammation, no fungus. The feedings are every Friday, once a week, and they fed some last Friday already, much less than they normally would but they fed, which is a great sign things aren't that bad.

 

[thebiggerthebetter]

I had thought this was just a dominance dispute. Looks like I was wrong and this is a pre-spawning mate selection process. I am much surprised (as an ignorant person would be) but this is an exciting and interesting learning!

I am told that the tail biting is definitely a pre-spawning behavior but the RTCs won't naturally spawn in that size tank, especially without substrate to build a pit nest. These hurdles can be overcome with multiple injections of two different hormones. There is a time interval depending on water temperature and dissolved oxygen levels, and then a waiting period to watch for the best time to harvest gametes for dry fertilization. One method is to observe the interaction between induced fish, another method is to periodically cannulate a small sample of eggs to see how close to ripe they are getting. One aims to neither harvest too early, nor too late (over ripe). The behavior shown in video means the female RTC is about 1 - 3 hours off peak production. Notice how the other RTCs are watching but keeping distance.

RTC are routinely farmed in Asia now, e.g., breeding naturally in Thailand lakes. RTC guard their nests to some degree.

There is a difference between mate selection and spawning event. It is fathomable that the nest building would require a lot of tail and body scrapes and the spawning would require a lot of energy and strength, so the RTC biting during mate selection isn't for the purpose of inflicting damage but rather to test the strength and endurance of the potential mating partner.

 

[thebiggerthebetter]

 

[fishdance]

I just looked at your "cold case" on the last page. I've kept RTC at 17 ~ 18 degrees Celsius in big tanks (15,000L + volume) through our winters which last 10 weeks. They do survive but eat less, slow right down and become prone to bacteria and parasite infections so not really worth the money saved on electricity.

Also had a quick look at the planetcatfish link, definitely ammonia damage resulting in septicaemia. Gill and blood poisoning suspected to my eyes. I didn't read everything thoroughly, you might have already reached the same conclusion.

All part of keeping challenging fish.

 

[thebiggerthebetter]

 

[thebiggerthebetter]

 

[thebiggerthebetter]