angels fighting

[john connolly]

why are my two angels fighting every time i do a water change this can last two days

 

[Colin_T]

They don't like each other. Freshwater angelfish need a tank that is at least 4 foot long and there should be at least 6 in the group. they need to choose their friends and partners and if you only have 2 males (instead of a group), they fight. If your tank is big enough and the water chemistry (GH, KH, pH) are suitable for angelfish, maybe get some more. Otherwise separate them.

 

[MaloK]

Try changing the water less often and change less water.

Angelfish in your aquarium getting angry?

 

[Uberhoust]

I have a number of angels and water change events are a big deal for them. If I am going to get any of them breeding it will be after I change the water. The process seems to trigger them to re-establish their relationships with the other fish in the tank. I have no evidence, but I often thought it could do with pheromone concentrations in the water. Before the water change if they release any pheromones (I don't know if they do), the concentration must be pretty high, which might cause some inhibitory behaviors, high pheromones might be interpreted as dense living conditions where fighting and mating are detrimental to the population, but with the water change the pheromones are much reduced leading to the fish exhibiting more behaviors associated better water and breeding time. This is just a thought; I have no way of really proving this.

In regard to the fighting, is it serious? If the fish work out who stakes out their portion of the tank without either fish damaging the other then you might be able to put it down to typical cichlid aggression but if fins or the bodies are being damaged or if they are locking jaws together then you might want to consider providing zones in the tank where they cannot see the other fish easily.

I have setup tanks with feature hardscape plunked in the middle of the tank effectively making one side for one angel and the other side for the other angel. Alternatively, I have had angels that do not get along with anyone and have had to put them in their own tank, this has been common event for me. Angels are really funny about who they like and who they don't and you will have to accept you might have to change things around to get to a place of peace in the tank. If you do get a tank configuration that works don't change it otherwise the behaviors might come back.

Good luck.

 

[Uberhoust]

Try changing the water less often and change less water.

First time I heard that but fits with my experience, I still like to do large frequent changes and control which fish live in which tank because I don't believe in a natural environment that the concentration of urine in the water would ever reach what occurs in your typical aquarium.

 

[MaloK]

First time I heard that but fits with my experience, I still like to do large frequent changes and control which fish live in which tank because I don't believe in a natural environment that the concentration of urine in the water would ever reach what occurs in your typical aquarium.

Yeah I wasn't fond on that method at first too. But with time I was able to balance the size and frequency of the water changes to keep the water clean and limit the crazy behaviors ensuing.

 

[Fishfunn]

why are my two angels fighting every time i do a water change this can last two days

You probably have two of the same sex. Clean water change spurs their mating instincts to breed and they are fighting for territory. I would follow @Colin_T's advice.

 

[TwoTankAmin]

I have kept angels and I do weekly water changes on all my tanks. I have never noticed any increase in hostile behavior as the result of a water change but I kept my fish different;y than they did in the experiment.

I tracked down ther paper involved and of you are curious you can read it here: https://repositorio.unesp.br/bitstream/handle/11449/175352/2-s2.0-85031507223.pdf.pdf?sequence=1

I had a lot of issues with the design of what they did and do not consider it as being a valid conclusion. They random;y picked the fish to be in each tank. When fish groups form a hierarchy this take s time and usally involves larger numbers. I would say the experimental design was almost intended to produce the results they got.

When I kept or still keep angels they do not behave as described in the paper. For one I start with a larger group than 3 and let them grow up together. I let them form pairs and then deal with that. I also keep them in planted tanks with space and cover. And even more interesting is I have kept Altum angels. These actually need to be kept in groups as adults. The only time angels need to be isolated is when breeding pairs form. To breed angels you need to put such a pair in their own tank as they will become extermely hostiles and protective of potential young.

When they are kids and teenagers their behavior can still be aggressive, but it does not compare to them as adults. They will even kill each other and also other tank mates they feel might be a threat to the eggs, wigglers or fry. Cichlids fight, it is in their nature. And when in spawning mode they often become murderous.

And then there is this, when one change 50 of the water in a tank. especially one with any substrate and/or decor. we actually decrease the volume of water by more than 50% it also reduce the available space by even more. So this is effectively forcing the fish into a smaller territory. This will encourage fighting not diminish it. And when a group of angels goes into squabbling mode, it can take some time for this to abate. With adults as opposed to juveniles, this is even moreso the case

So for me it boils down to this. Suppose the researchers had used much bigger tanks with plenty of cover so the fish have a way to run and hide? What if they had tried the experiment with only two angels which had paired off?

I would call what these folks did as sloppy science at best and that their conclusions are not on very solid ground. Consider that the paper was published in 2018. Yet in the 6 or so years since it has only been cited 20 time.

Less water renewal reduces effects on social aggression of the cichlid Pterophyllum scalare​

AC dos Santos Gauy, CNP Boscolo… - Applied Animal …, 2018 - Elsevier
… Pterophyllum scalare, a popular ornamental cichlid species (Huntingford et al., 2012). We
predicted that the amount of water renewed … Thus, by knowing the effect of the amount of water …
Save Cite Cited by 20 Related articles All 7 versions

Finally, they talk about chemical and hormonal cues in the water affecting behavior. Well, in the wild thise cues are washed away or diluted rapidly. In a small tank they are not. What about the possibility that when these things build up in a tank before a water change, that is what effects behavior. It makes the angels less agressivie than they naturally would be. Then claean up the water and the normaly squabbling returns?. And then they allowed 4 days for a heieracrhy to establish. My experience is things can take weeks or even months depending on the size of the group.

edited for spelling and typos

 

[Back in the fold]

They don't like their world being disturbed and they’re fighting because they both think the other guy caused the disturbance . Spend a little time looking at them before you do your water change and then proceed slowly so they know it’s you doing it .

 

[john connolly]

thanks for all replies