Betta died, need help to find out the cause

[Renzo77]

Sadly, my betta passed away and I'm trying to find out the cause since he's not the first betta to die in a similar way. He was ok for 2 weeks in a heavily planted 20 gal tank already stocked with some cardinal tetras and seemed naturally lazy ever since I bought him, which I believe was a personality trait although it could not have been.

Ammonia levels were 0, nitrite levels were 0 and my nitrates were 40ppm(its the same straight out the tap) however I was in the process of reducing the nitrate levels with a new pozzani filter by gradually replacing 20% of the water daily to reach around 20 ppm in the tank.

I first noticed something was wrong when he suddenly couldn't swim and kept sinking to the bottom of the tank and so took the actions needed for swim bladder disorder by placing him in a bucket full of tank water(1 inch deep) and placed a heater, air stone and a slab of rock to hide under. I proceeded to starve him for 3 days and on the 4th I attempted to try feed him peas however seemed to have lost appetite. I also noticed he didn't poop at all in the time he was in the bucket which made me believe he was constipated.

Later on that day he suddenly started swimming sporadically around the bucket until he eventually stopped with his mouth wide open and passed away.

As I said before I had a betta(female) who died similarly where she just one day couldn't swim up and died the same day in the same tank. This was around 2 or 3 years ago so I have no idea if it's right to link the 2 scenarios and both bettas came from different aquatic chain stores. Many people online said that swim bladder disorder isn't fatal and if it was, it was because of disease yet there weren't any other visible symptoms except a slightly bloated swim bladder poking out from one side.

Any thoughts on what might have caused his death?

 

[PheonixKingZ]

He may have died of stress. The water in the bucket may not have been the same parameters as in the tank.

All of that points to swim bladder disorder in my book. What did you feed him? Did you add anything to the tank recently? How old was he?

 

[Byron]

Diagnosing fish disease is a very difficult task. For one thing, many symptoms visible to us can be caused by different underlying issues. We see "swim bladder" mentioned a lot, but this can be genetic, internal protozoan, parasites, ammonia, nitrite, high nitrate, temperature (too cold usually), poisoning by some toxin in the water...etc. You can have a microbiologist perform a necropsy to determine the cause of death, or sometimes knowing the data can allow us to ascertain with a relative degree of certainty what may have happened.

On a related issue, male bettas should not be housed with other fish. This is almost certain to cause anxiety for the betta, and possibly the other fish too. Again you may not "see" this, but it is there because it is the inherent nature of the respective species. I just posted at length on this topic, it is worth a read. I'll copy from the earlier thread.

This topic comes up quite often, and many still do not grasp the issue. Not casting aspersion on anyone, I will just try to explain the reality.

Male Bettas are not community fish. They should always be on their own in a suitable tank. The reason this is fact has to do with the inherent normal and natural make-up of the fish. The DNA. Ichthyologists who study a species are able to discern its inherent behaviours. We take these to be the way the individual fish in the particular species will behave, interact, respond to external stimuli, respond to the environment, etc. It describes the species, in effect, so far as these aspects of its physiology and life are concerned. It is the "norm" for the species, and the majority of individual fish in that species will adhere to these norms.

Individual fish within a species may not always follow the norm. There are several reasons for this. Any environmental factor that the fish "expects" but which is not provided can affect its behaviourial response. For example, it is well established that when a shoaling species does not have sufficient numbers of its own, aggression will increase in most of the individual fish. This is simply the fish's way of responding to what it sees as adverse environmental conditions. Sometimes the fish's response will be the opposite. But what must be understood is that the fish has expectations programmed into its DNA and when certain of these are missing it is going to react somehow.

Back to our male Betta. Placed in with other fish, the betta's "normal" response is to drive the fish out of his territory. The fish purchased today have had this response heightened through breeding. So we should expect trouble, and the only way to avoid harm to the betta or the intended fish is to recognize the inappropriateness and not push the fish into what is for it an unnatural and foreighn environment. That is responsible fish husbandry.

It must also be understood that what we see is not always what is occurring. The fact that Betta "x" does not physically attack the other fish does not mean it is not still responding normally to an unacceptable (for the Betta) situation. The betta still regards the space as "his." He will be releasing chemical signals called pheromones (read by others of that species) and allomones (read by other species), and these can cause severe stress just as much as physical interaction, even though we cannot see them. We may however see the result, sooner or later. More than one member here has reported that all was well with their betta and his tankmates, only to have the member wake up one morning and find dead fish and the betta laying down the law.

It can work in reverse too. Small shoaling fish when confronted with a betta can also respond physically, nipping fins is common, or via allomones. All of which will stress the betta, maybe unseen, until it is too late.

The bottom line is to accept the norm for a species and provide accordingly. Anything else is taking a risk,and responsible aquarists should not deliberately go down that road. It is not fair to the fish, and it is in fact inhumane. As Paul Loiselle, an acknowledged cichlid authority, says in the citation in my signature.

 

[Renzo77]

He may have died of stress. The water in the bucket may not have been the same parameters as in the tank.

All of that points to swim bladder disorder in my book. What did you feed him? Did you add anything to the tank recently? How old was he?

I don't remember adding anything to the tank. I do think it could have been what I've fed since i fed him pellets that were mostly dry and not pre-soaked and sometimes flakes and freeze-dried tubifex. I'm pretty sure he was quite young considering his size and comparing it to fully grown bettas, maybe a year or less old.

 

[PheonixKingZ]

I agree whole heartedly with @Byron, Bettas are not community fish and shouldn't be kept as such.

Who knows? Maybe it died of stress, maybe it was just its time to go. I am sorry for your loss...

 

[Fishmanic]

How old was the Beta...I have heard that they could be a year old when you buy them in the fish store.

 

[PheonixKingZ]

How old was the Beta...I have heard that they could be a year old when you buy them in the fish store.

On average, its anywhere between 3 months - 12 months.